The grass and grain joint-worm flies and their allies : a consideration of some North American phytophagic Eurytominµ

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Title:
The grass and grain joint-worm flies and their allies : a consideration of some North American phytophagic Eurytominµ
Series Title:
Technical series / U.S. Dept. of Agriculture, Division of Entomology ;
Physical Description:
24 pages : illustrations ; 23 cm.
Language:
English
Creator:
Howard, L. O ( Leland Ossian ), 1857-1950
United States -- Division of Entomology
Publisher:
G.P.O.
Place of Publication:
Washington, D.C
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Subjects

Subjects / Keywords:
Eurytomidae -- Anatomy   ( lcsh )
Gall wasps -- Anatomy   ( lcsh )
Harmolita -- Anatomy   ( lcsh )
Phytophagous insects   ( lcsh )
Parasitic insects -- North America   ( lcsh )
Genre:
bibliography   ( marcgt )
federal government publication   ( marcgt )
non-fiction   ( marcgt )

Notes

Bibliography:
Includes bibliographical references.
Statement of Responsibility:
by L.O. Howard.

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University of Florida
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All applicable rights reserved by the source institution and holding location.
Resource Identifier:
oclc - 63269764
ocm63269764
System ID:
AA00026343:00001

Full Text


TECHNICAL SERIES No. 2.

U. S. DEPARTMENT OF AGRICULTURE.
0
DIVISION OF ENTOMOLOGY.






THE





GRASS AND) GRAIN JOINT-WORMI FLIES


AND



THEIR ALLIES:



A CONSIDERATION OF SOME NORTH AMERICAN
PHYTOPHAGIC E URYTOMINAE.


BY


L. (). HOWAR D
ENT( )MOLOGIST.


















WASHINGTON:
GOVERNMENT PRINTING OFFICE.
1896.

























LETTER OF TRANSMITTAL.



UNITED STATES DEPARTMENT OF AGRICULTURE,
DIVISION OF ENTOMOLOGY, Washington, D. C., February 5, 1896.
SIR: I have the honor to submit for publication the second number of the technical series of bulletins of this office, intended especially for working entomologists, and to be distributed also to learned societies and to periodicals and libraries. The phytophagic Eurytominm here considered, mainly from the classificatory standpoint, work in the stems of grasses and small grains and in the seeds of grapes.
Respectfully,
L. (. HOWARD,
Entomologist.
Hon. J. STERLING MORTON, Secretary of Agriculture.
3




































CONTENTS.


Page
Introduction --------------------------------------------------------------- 7
Analysis of genera --------------------------------------------------------- 7
Genus Isosoma ------------------------------------------------------------- 8
Isosomorpha -------------------------------------------------------- 20
Eurytomocharis ----------------------------------------------------- 21
Evoxysoma --------------------------------------------------------- 22
Decatomidea -------------------------------------------------------- 23
5
















ON SOME AMERICAN PHYTOPHAGIC EURYTOMINIE

By L. 0. HOWARD.
Ten years ago, when Prof. F. M. Webster, then a field agent of this division, was engaged in studying certain grain-stalk and gras -stalk insects in Indiana and Ohio, and at about the time when he succeeded in securing the material upon which Dr. Riley established, with his assistance, the fact of dimorphism and alternation of generations of Isosoma tritici and I. gr((nde, he collected and reared several other species of Isosoma, and a little later Mr. Koebele, in California, also an agent of the division, reared several additional species. At that time the writer drew up a rather careful paper on the genus as it was then understood, characterizing all the new forms, and had competent figures of the most important species prepared. The manuscript
was then laid aside in the hope that further facts would be ascertained concerning the life history of some of the species which would render the account more complete. Other matters have interfered, however, with the proposed studies, and as the importance of placing the facts already collected upon record and of describing and naming the new forms seems great, the whole subject has been carefully gone over again in the light of recent papers which have been published (especially by Mr. Ashmead), and which involve certain generic changes in the subfamily Eurytomime, and the results are presented herewith. The writer has included in his account only the species which have been reared or of which we know the habits with some certainty. There are several additional species in Mr. Ashmead's collection and in the collection of the National Museum, but we do not know their specific habits, and they are omitted from )resent consideration on that account.
The species here treated are included in five genera, the females of which may be separated by the following table:

ANALYSIS OF GENERA.
Females.
Metathorax much lengthened.
Metanotum sloping, rounded behind ------------------------------ Isosonla
Metanotum quadrate, abruptly truncate behind ------------------- isoomorpha
Metathorax not lengthened.
Postmarginal vein longer than stigmal, butnot twice as long.
Parapsidal furrows obliterated posteriorly -------------------- Decatonidea
Parapsidal furrows complete, distinct ---------------------- Eurytomoeharis
Postmarginal vein twice as long as stigmal ------------------------- Eoxysoma
7





8

Genus ISOSOMA Walker.
There is no longer any question as to the phytophagic habits of Walker's genus Isosomna, although they were questioned by E. A. Fitch as late as 1882. The careful observations of early American writers, particularly Harris, Asa Fitch, Walsh, and Riley, had fixed the status of Isosoma hordei as a plant-feeder beyond all peradventure, but their conclusions were not accepted by certain English entomologists until Westwood had published his careful studies on Isosoma orchidearum and until Weyhenbergh had called attention to his earlier observations on a Dutch species. (See the writer's paper on the Biology of the Chalcidide, Proc. U. S. Nat. Mus., vol. xrV, p. 585.) In addition to I. hordei Harris, the fact of phytophagy was established by Asa Fitch for his I. secale,i tritici, hordei, and fulvipes. The last of these, as we have shown by comparison of the type specimens, is synonymous with Harris's .L hordei, and the third, therefore, through preoccupation of the name, needs a new designation. Riley has also proved conclusively that his I. tritici (here treated as I. grande) is phytophagic. Of the other species which we treat below, the plant-feeding habit is perhaps not absolutely proven in each case, but the insects are structurally so closely related that, taken in connection with the proof at hand, this habit cai not be doubted. The true European Isosomas have now practically all been accepted as plant-feeding species. Schlechtendal, in his "Die Gallbildungen der deutschen Gefiisspflanzen" (Jahresbericht des Vereins fiir Naturkunde zu Zwickau, 1890), gives thirteen species of this genus as true gall makers in Europe.
Owing to the fact that aiin alternation of generations connected with a peculiar dimorphism has been established in the case of I. tritici Riley (= I. grande, ftormi minutum) and I. grande Riley, it is quite likely that a similar pliheniomenon will be found to occur with more than one of the following species. In the. majority of cases, however, the males have been associated with the females, and where species have been described from the females alone, these have been large and wellformed individuals, with no trace of degradational characters, such.as the absence of wings, which would indicate that they are parthenogenetic forms. Moreover, I. tritici Riley has a somewhat different facies from the other members of the genus, consisting largely in its smooth aspect and one or two other minor points, which practically associate it with Haliday's genus Philachyra. While the writer is not inclined to give Philachyra generic importance, and considers that its species should be still associated with the true Isosomas, these feeble characters may still be associated with the phenomenon of dimorphism, and SWalsh considered Fitch's species as synonymous with hordei since they were distinguished almost entirely by the coloration of the legs. Careful study, however, of Fitch's types, now in the possession of the United States Department of Agriculture, shows them to be distinct in other characters.






9

we may not find this characteristic present with more typical Isosomas. This supposition is to a certain extent supported by the fact that an examination of certain of Portschinsky's species of Russian Isosomas, sent us by Professor Portschinsky some years ago, shows that his I. apterum and L. eremitum belong to the smooth Philachyra group, and that the former, as the name shows, is wingless. It may further be considered suggestive that only females of apterum were received from the Russian writer, while both a male and a female of eremitum were received. Does this niiot immediately hint at a possible alternation of generations with these two so-called species? This coincidence
further suggests that Philachyra may be a valid genus after all, even though we are able to separate it from Isosoma by no other morphological character than the sihoothness of the integument.

ANALYSIS OF THE SPECIES OF ISOSOMA.

Females.
Mesonotum smooth, polished, shining.
Winged................................................---------------------------------------------.....grande, form grande
Wingless................................................ ---------------------------------------------grande, form minutum
Mesonotum coarsely, more or less umbilicately, punctured.
Pronotal spot wanting ................................................---------------------------------------------... bromi
Pronotal spot moderately large and rather distinct--------------------....................... hageni
Mesonotum rugulose, shagreened or coriaceous; not umbilicately punctured.
Thorax nearly smooth, feebly shagreened or coriaceous and more or less shining.
Central furrow of metanotum incomplete .....................-----------------------...... websteri
Central furrow of metanotum complete.
Metanotal furrow with a complete median longitudinal carina.
Cheeks very full and hairy ................................ hirtifrons
Cheeks not especially full and hairy ................------------------.... maculatumn
Metanotal furrow with no median carina.
Metanotal furrow shallow and transversely striate----------............elymi
Metanotal furrow strongly emarginate; not striate-------........bromicola
Metanotal furrow with an incomplete median longitudinal carina..fitchi
Thorax more coarsely shagreened or finely rugulose, opaque or subopaque.
Abdomen shorter than thorax.
Much shorter than thorax, subglobose ........................---------------------agrostidis
Nearly as long as thorax, oblong oval........ ..........----------------------...... captivum
Abdomen longer than thorax.
Pronotal spot minute .........................................---------------------------------------.... hordei
Pronotal spot large, distinct.
Second abdominal segment longer than fourth and fifth together
secale
Second abdominal segment shorter than fourth and fifth together
tritici
Isosoma (Philachyra) grande Riley (fig. 1).
8Iso8oma tritici Riley, American Naturalist, March, 1882, p. 247.
Isosoma grande Riley, Ann. Rep. U. S. Dept. Agric., 1884, p. 358.
This species differs at once from all the other American forms by its smooth, polished, and shining mesothorax. Next to hordei it is the best known and most important, economically speaking, of the North American species. It is the only species of Isosoma for which a true







alternation of generations has been established. The small wingless form, originally described by Riley as tritici, is the vernal generation, and consists of both sexes. The large winged form, described as grande, is the summer generation, and consists entirely of females. The species is widespread, occurring through the middle belt of country from the Atlantic to the Pacific, and has been reared only from wheat stalks.
The name tritici Riley falls on account of its preoccupation by Fitch. Dr. Riley was familiar with Fitch's name, but revived it for the present species, thinking with Walsh that tritici Fitch was a synonym of hordei Harris. Riley's name, however, even in that event, would have been rejected under the law of "once a synonym always a synonym." The dimorphism in this species is fortunate, since it enables us to retain


ip












FIG. 1.-hIsosoma grande Riley.
Riley's name for the summer form as the specific name. The species must, therefore, be known as follows:
losoma grande Riley.
Form grande=wingedl summer generation.
Form minuturm I proposed in place of tritici)=wingless spring and winter
generation.
Isosoma californicum n. sp.
Fenmale.-Length, 5 mm.; expanse, 8 mm. Head and thorax rather coarsely umbilicate-punctate; petiole distinct, but short and stout; abdominal segments 5 to 8 shorter than 4, 2 and 5 subequal, 3 and 4 subequal; mesoscutellum pointed at tip, axille nearly meeting; metanotum with a straight central longitudinal groove which is regularly concave from side to side and slightly emarginate at borders; each side of the groove the metanotum is coarsely umbilicate-punctate; hind coxm plainly granulate above. Antennm rather short and stout; joints
'For a good figure of form minutum, see Ann. Rept. Dept. Agric., 1881-82, plate xii, fig. 3







well separated, cup-shaped; funicle joint 1 about as long as pedicel, but longer and narrower than succeeding joint; joints 1-4 each slightly wider than preceding joint; club ovate, as long as two preceding funicle joints together. Abdomen longer than thorax, shining, with very faint sculpturing; penultimate and antepenultimate segments with abundant white pile, which also occurs on the pygidium as well as the head and thorax; spur of stigmal club given off just before tip and reaching farther toward apex of wing than does tip of club; prouotal spot lacking, pronotum uniform jet black, as is the rest of the body; the place ordinarily occupied by the yellowish pronotal spot somewhat sunken, has a finer sculpture, and is lacking in the white pile found elsewhere on the thorax. All legs uniform dark honey-yellow except coxa', which are black; scape (lark honey-yellow; wing veins light brownish-yellow.
Male.-Closely resembles female. Antenna long and stout; scape slightly expanded below; pedicel small, globose; funicle joints strongly arched above, not constricted in middle, markedly pedicellate, and each with two half whorls of long hairs; funicle joint 1 nearly twice as long as 2; 27 3, 4, and 5 subequal in length; club elongate, pointed, as long as two preceding funicle joints together. Punctation somewhat less distinct; legs black, except tarsi and tips of femora and tibiae, which are yellow; petiole stout, as long as first abdominal joint.
Described from 5 females and 10 males captured April 20, 1891, by Albert Koebele, in the upper part of Shepherd's Canyon, Argus Mountains, California, upon Eriocoma cuspidata. The insects were collected in numbers at rest upon the upper part of the plant just before dusk. Upon examining the grass stalks Mr. Koebele found that they contained holes from which the Isosomas had apparently emerged. Isosoma bromi n. sp.
Female.-Length, 3.4 mm.; expanse, 5.6 mm. Head and thorax densely umbilicate-punctate, punctations rather finer and closer than in preceding species; pronotal spot wanting; abdomen without a trace of sculpture, not longer than thorax, but more swollen than in preceding species; mesoscutellum and mnetanotum as with californicum, except that the metanotum each side of median groove is not so coarsely punctate; claw of stigmal club strongly carved; front coxoe honey-yellow, middle and hind coxae black; front femora and tibiae honey-yellow, middle femora honey-yellow, tibiw, darker, hind femora and tibia' dark brown, yellowish at joints.
Male.-Length, 3 mm.; expanse, 5.4 mn. Antenna' as with caltfornicum, except that joint 1 of funicle is less than twice as long as 2, and is regularly furnished with long hairs not arranged in whorls. Petiole slenderer than with preceding species, little longer than coxa', and not as long as first segment of abdomen.
Described from 2 females and I male reared from Bromus ciliatus, in May and August, 1887, at Los Angeles, Cal., by Albert Koebele.





12

Isosoma hageni nii. sp.
Female.-Length, 4 mm.; expanse, 7 mm.; head and thorax rather coarsely reticulate-punctate, the interspaces of the reticulations finely granulate. Metanotum with three faint subparallel longitudinal submedian caring. Pronotal spot moderately large and rather distinct. Abdomen a little shorter than the thorax, second segment occupying about one-third of its dorsumni; segments 3, 4, 6, and 7 subequal; segment 5 a trifle longer. Petiole rugose, stout; hind coxm faintly shagreened. Aniitenn;e notin good condition for study in the two specimens at hand-broken in one and with the pupal sheaths in the other. Stigmal club, rounded; spur distinct, straight.
Color, black; apical third of front femora and tibia and tarsi of the same legs, honey-yellow; knees and tarsi of middle and hind legs also honey-yellow; pubescence of entire body short and sparse, light in color.



//











Fla. 2.-Isosoma aqrostidis Howard.
Described from two female specimens from the collection of the Museum of Comparative Zoology, Cambridge, Mass., labeled in the handwriting of Dr. Hagen, "Ii quick grass, Boston, March, 1883, H. H7." Isosoma agrostidis nii. sp. (fig. 2).
Female.-Leagth, 2.8 mm.; expanse, 5.2 mm. Head and mesothorax finely shagreened and also very sparsely and finely rugulose; metanotum somewhat coarsely rugulose and without a median furrow, but with a rather faint median longitudinal carina; mesoscutellum rather rounded at apex, not sharply pointed; axillar and parapsidal sutures nearly meeting; pronotal spot evident but small, scarcely seen from above; first funicle joint of antenna not twice as long as second; remaining joints subequal, somewhat rounded; club joints very distinct, terminal one acuminate and styliferous. Abdomen short and stout, considerably shorter than thorax; subglobose in shape, its see-





13

ond segment occupying nearly half of the whole surface; segments 3 to 7 short, subequal. Entire body very free from pilosity, except metanotal fimbria, which is pronounced and white, and except hind coxe which have slight whitish pilosity on the outer side. Claw of stigmal club straight, issuing from tip of club and extending considerably beyond it, club itself abruptly truncate, triangular. Entire body, including legs, black, except pronotal spot, femoro-tibial knees and tarsi, which are dark honey-yellow.
SDescribed from two female specimens reared by Albert Koebele, from small galls occurring rarely upon a grass of the genus Agrostis, collected at Summit, Placer County, Cal., in September, 1885. The galls were distinct elliptical swellings about 7 to 10 mm. long and from 2 to 3 mm. in greatest diameter, and occurred upon different parts of the stalk.
Isosoma captivum n. sp. (fig. 3).
Female.-Length, 3.4 mm.; expanse, 5.8 mm. Head and mesonotum uniformly, finely, and closely rugulose, not shagreened; metanotum















Fi. 3.-Iswosna captruino Howard.
more coarsely rugulose and with a narrow and shallow central longitudinal groove which widens slightly posteriorly; pronotal spot plain, moderately large; hind coxe delicately punctate. Abdomen shiny, as long as thorax, oblong-ovoid; the second segment occupying nearly one-third the whole surface; segments 4 to 6 subequal, the third a little shorter; funiclejoints 2 to 5 subequal; club nearly as long as three preceding joints; joint 1 one-half longer than 2; pile sparse and short, more marked at metanotal fimbria and terminal joints of abdomen than elsewhere. Color uniform black, except for pronotal spot, tarsi, middle and hind femoro-tibial knees, front tibiae and apical third of front femora, which are light honey-yellow. Stigmal club about as in preceding species, except that its tip is more rounded instead of squarely truncate.
Male.-Length, 2.5 mm.; expanse, 5 mm. Punctation rather finer than with female; petiole as long as first abdominal joint, strongly





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rugose; flagellum of antennae long; pedicel not globose, slightly elon. gate; joint 1 of funicle longest, twice as long as pedicel; joints 2, 3, 4, and 5, each a little shorter than its preceding joint; not so strongly pedicellate as' with I. californicum and L. bromi, moderately arched above with the hairs arranged in two indefinite whorls; club separated into two subequal pedicellate joints, giving tunicle the appearance of being 6-jointed instead of 5-jointed, as with bromi and californicum; scape short, about as long as pedicel and first funicle joint together; strongly expanded below tip. Coloration like that of female.
Described from 17 females and 12 males captured by Prof. F. M. Webster, in May, 1885-86, at Normal, Ill, and Lafayette, Ind, on blue grass.
Isosoma elymi French (fig. 4).
Iaosoma elymi French, Canadian Entomologist, vol. xiv, p. 9, 1882.
Female.-Length, 3.8 nun; expanse, 7 mm. Head and mesonotum delicately shagreened, not rugulose; metanotum with a central longitudiFIG. 4.-Isosoma elymi French.
nal furrow, rather broad and shallow and transversely striate; each side of the posterior two-thirds of the groove is a broad, flat space, closely and finely granulate; abpve this space is a coarsely rugulose area; pronotal spot very large and conspicuous, occupying one-half of the dorsal aspect of the anterior border of the pronotum. Entire body rather closely but finely pilose. Antenne unusually hairy; joint 1 of funicle nearly twice as long as joint 2, which is about the same length as pedicel; joints 3, 4, and 5 about equal to 2; club as long as three preceding joints together. Abdomen as long as thorax; joint 2 as long as 3, 4, and 5 together; joints 4 and 5 subequal, 6 and 7 a little longer. Scape and legs black; apical one-third of anterior femora, front tibie, all tarsi, and knees of middle and hind legs, honey-yellow; the pronotal spot lighter yellow; claw of stigmal club given off just before the





15

tip and not exteniiding farther than tip of club in the direction of apex of wing.
Redescribed from 1 female specimen reared from Elymus americanus at Carbondale, Ill., April, 1882, by Prof. G. H. French.

Isosoma maculatum n. sp.
Femdle.-Length, 3.8 mm.; expanse, 5.4 mm. Sculplturing of head and mesonot um as with preceding species; metanotum with a very shallow, scarcely margined, central longitudinal furrow, including throughout nearly its whole length a median longitudinal carina; the rest of the sclerite irregularly and coarsely rugulose, the elevations mainly taking a longitudinal direction; hind coxa faintly granulateabove; pronotal spot very large, even more pronouced than with preceding species and covering two-thirds of dorsal aspect of fore border of pronotum; axilhe meeting at tip. Antennm as with preceding species, except that club is decidedly flattened from sides. Abdomen smooth and shining, not quite as long as thorax; segments 3 to 5











IJ



FIG. 5.-Isxoma websteri Howard.
slightly and gradually increasing in length; joint 6 a little shorter than 5; flagellum of antennm rather shorter than preceding species; relative proportions of joints libout the same. Body sparsely hairy; stigmal club as with preceding species. Coloration as with preceding species.
Described from two female specimens collected oin blue grass May 19, 1886, and June 3, 1885, at Lafayette, Ind., by Prof. F. M. Webster.

Isosoma websteri n. sp. (fig. 5).
Female.-Length, 3.4 mm.; expanse, 6.3 mm. Head, pronotum, and mesonotum as with preceding species; metanotum with only the beginning of a central furrow, its lateral caring immediately curving around to the sides, each inclosing an oval, flattened, nearly smooth portion of the metascutellum; a median carina extending nearly to the tip of the





16

sclerite; pronotal spot moderately large and plainly seen from above, occupying a little more than one-third of the dorsal aspect of the pronotal foreborder. Abdomen much longer than thorax; segments 3 to 5 increasing in length; 6 and 7 as long as 5. Antennm with joint 1 of funicle twice as long as 2; joints 3, 4, and 5 gradually decreasing in length, subequal in width; joint 5 more closely connected with club than with preceding joint. Color and wing venation as with preceding species.
Described from 7 female specimens collected on wheat at Normal, Ill., by Prof. F. M. Webster, in May, 1884. Isosoma hirtifrons n. sp. (fig. 6).
Female.-Length, 3.7 mm.; expanse, 7 mm. Sculpturing of head, pronotum, and mesonotum as in preceding species, except that there are sparse, large, shallow punctures on mesoscutellum; cheeks much fuller than in other species; metanotum as with I. maculatum. Abdomen















F;. 6 -_Issoma hirtifrons. Howard.
about as long as thorax; segments 3 to 6, increasing in length. Antenun stout, moderately long, very hairy; proportions about as in preceding species. Body not unusually pilose, except face, which is closely covered with short white pile; pronotal spots very plain, but not large, occupying about one-third of the dorsal aspect of the fore-border of the pronotum. Color black, except for all femero-tibial knees and pronotal spot. Claw of stigmal club given off some distance before tip, delicate and short.
Described from 4 female specimens reared by Mr. D. W. Coquillett March 13, 1886, from rye stalks which he collected in Mercer County, Cal., June 211 1885.
Isosoma bromicola n. sp.
Female.-Length, 3.1 mm; expanse, 4.6 mm. Punctation of head, pronotum and mesonotum like that of I. maculatum, which it also resembles






17

in the large pronotal spots. Metanotum with a distinct, strongly emarginate central longitudinal groove, the space either side finely granulate, with occasional irregular carinme. Abdomen longer than thorax; segment 2 as long as 3, 4, and 5 together; 5 and 6, subequal. Antene rather long and straight; pilose; joint I o)f funicle only slightly longer than joint 2; club not quite as long as three preceding joi its together, strongly flattened from side. Face very slightly pilose; metaiotal fimbria sparse. The whole insect is smaller, slenderer, and imiore delicate in appearance than aity except grande, form minutrn.
.Male.-Length, 1.9 mm; expanse, 3.4 mm. Petiole short, not as long as first abdominal segment and scarcely as long as hiiiid coxze. scape of antennae slightly widened; funicmle joints very slightly rounded above and very slightly pedicellate; each more than twice as long as pedicel and each faintly constrictedi n middle; club divided into two pedicellate joints as with L. captivun. All legs black with light-yellow knees.
4















FI. 7.-Isosoma tritiri Fitch.
Described from 11 females and 7 males reared by Mr. Albert Koebele, at Los Angeles, Cal., from Bromus ciliatus collected at Millard's Canyon, Los Angeles County, Cal. The adults issued in March, 1887, from grass collected September, 1886.
Isosoma tritici Fitch (fig. 7).
Eurytomia tritici Fitch, Jour. N. Y. State Agricultural Society, 1859, vol. x, p. 115.
8sosoma hordeiWalsh, Amer. Entomologist and Botanist, Oct., 1870, vol. u, )p. 332.
Decatoma basilaris Provancher, Faun. Ent. Can., vol. n, p. 569.
Isosorna nigrum Cook, Rural New Yorker, June, 1885, p. 314.
Fermale.-Length, 4 mrm.; expanse, 7.6 mm. Head, pronotum, and mesonotum strongly rugulose but not umbilicate-punctate except toward tip of scutellum, where an occasional umbilicate puncture occurs; metanotum also strongly rugulose with a faint trace anteriorly of a median longitudinal furrow; metanotal spiracles large and per12284-No. 2- 2





18

fectly circular; pronotal spots moderately large and often faint, but plainly discernible from above, sometimes, however, quite bright and distinct. Abdomen longer than thorax, nearly as long as head and thorax together; abdominal segments 4 and 5 together longer than 2; 3 only about half as long as 4, and 5 as long as two preceding united; first funicle joint one-half longer than second; club longer than three preceding funicle joints together. Body slightly but plainly l)ilose except at sides of metanotum, where the fimbria is very obvious. Legs black except at joints, which with the tarsi are yellow. Claw of stigmal club given off before the tip.
Mfale.-Length, 2.9 num.; expanse, 6 mm. Petiole shorter than hind cox t', faintly punctate; flagellum of antennm uniformly pilose, joints well rounded abl)ove, not strongly pedicellate; joint 1 three times as long as wide and nearly three times as long as pedicel; none of the funicle joints constricted in the middle; joints 2 and 3 each nearly as long as 1 ;.joints 4 and 5 each a little shorter; club plainly divided by adistinct incision into two joints, but the terminal ovate joint is not pedicellate.
Redescribed from many male and female specimens reared in December anid January. 1SS5, from wheat stalks collected in Louisa County, Va.; from other specimens received from A. J. Cook, Lansing, Mich.; from others reared by J. H. Comstock, at Ithaca, N. Y., from straw col. lected in the iimed(liate vicinity; from other specimens received from J. A. Lintner, Albany, N. Y.; from specimens fr-om the Asa Fitch collectioni,labeled Eurytoma tritici Fitch, Maryland, E. L. Rogers;" from specimens collected )on grass at Lafayette, hid., by F. M. Webster; from specimens received from S. O. 1)iom, Grantsville, N. C.; from many specimens reared(l from Elym us america)nus by Albert Koebele, in Los Angeles, Cal., and from many moire specimens reared by the same gentleman from a grass which was supposed by Mr. Koebele to be either Bromus ciliatws or a species of Agropyrum, in the Santa Cruz Mountains, California.
Isosoma hordei 1 arris.
Ichlncumon hordci Harris, New England Farmer, July 23,1830, vol. ix, p.2.
Euirytoimafulripes Fitch, Seventh Rept. Ins. N. Y. (sep. ed.), 1862, p. 154.
Isonoma hordei (var.). Walsh, Amer. Entom., Oct., 1870, vol. ii, p. 330.
The writer is able to positively assert that Harris's I. hordei is identical with Fitch's I. fulripes. Fitch's types are in the possession of the United States National Museum, and through the kindness of Mr. Samuel Henshaw, of the Boston Society of Natural History, I have been able to critically examine Harris's types, consisting of 2 males and 2 females, fragmentary it is true, but perfectly recognizable. The specimens are labeled "281," and the record, as I am informed by Mr. Hensbaw, reads "281 Eurytoma hordei H. N. E. Farmer, Insect (parasiticd) in Barley, June 15, 1830."
Female.-Length,3.6 mm; expause,6 mm. Pronotum and mesonotum minutely but strongly rugulose, smoother than I. tritici; metanotum





19

more coarsely rugulose, the larger elevations taking a longitudinal direction, no central furrow or carina; pronotal spot very small, not visible from above. Abdomen as long as head and thorax together; joints 4, 6, and 7 subequal in length, the fifth a little longer; joint 3 a little longer that 4; 2 hardly longer than 3 and 4 united; funicle joints 2 to 5 submoniliform, but still a little longer than broad. All legs (except coxwe) and anteiine honey-yellow, flagellum and femora a little darker; claw of stigmal club straight, given off well before tip of club; pilosity sparse.
Male.-The only males which I have seen are the two from the Harris collection. These are both in very bad condition; neither has an abdomen and one has no antennae. With the ()other but three funicle joints remain on the left antenna (the others being broken off) and four oi the right, but the latter are still iiclosed in the pupal sheath. The three funicle joints remaining onil the left antenna are not pedicellate, very slightly arched above, and furnished with close, moderately short hair not arranged in whorls; joint 1 longest, 2 and 3 successively decreasing. Joint 4 is still shorter, judging from the sheathed right antellna.
Described from 14 female alnd 2 male specimens, two females front the Fitch collection, labeled in Fitch's handwriting "Eurytoum fulvipes Dlsio l~o If Entoitolog y,,J Jnuary '13 88 Fh.," ten females reared in the Division of Entomology, Jaary 23, 1883, from stems of barley received from W. Coup)er, "Canada West," and two females and two males from the Harris collection, reared from barley, June 15, 1830.

Isosoma secale Fitch.
Eurytoma secalis Fitch, Amer. Agric. Aug., 1861, vol. x x, p. 236.
Isosoma hordes (var.) Walsh, Amer. Entom., Oct., 1870, vl. L, i. 330.
1808111 ho Oct, 170,vol.it,1).330.
Female.-Length, 3.6 mm.; expanse, 6.6 nim. Functation as with preceding species; pronotal spot large, p)lainly seen from above. Abdomen as long as head and thorax; segments 4 and 5 subequal; 6 and 7 together shorter than 5; 2 much longer than 4 and 5 together. Color black; scape and legs black; frout tibiae, knees, and tips of middle and hind tibiwe and all tarsi honey-yellow; claw of stigial club given off near tip of club, somewhat curved; antenne as with pi eceding species.
Male.-Length, 3 mm.; expanse, 5 mm. Specimen in rather poor condition. Expansion of scape more abrupt ftromn tip than with other males described; funicle joints well arched above, scarcely pedicellate, each with two indefinite whorls of hair and with no median constriction; each joint twice as long as wide; club plainly divided into two joints, but no trace of pedicel to terminal joint, resembling hordei in this respect; petiole a little shorter than hind coxa and shorter than first abdominal segment.
Redescribed from one female and one male from Fitch's collection labeled Eurytoma secale.







Isosoma fitchi ii. sp.
EutrYloma hordei Fitch (nee Harris) Seventh Rept. ins. New York (author's editlin). p. 154, 1862.
Fernale.-Lengyth, 3 mm.; expanse, 5.8 mmn. Head, pronotum, and DIsono0tuim faintly sliagreened, nearly smooth, shining; mesoscutellumi with a few sparse punctuires; metaiiotuini with a complete inedian longitudinal furr-ow egin-(-nate oin the anterior half aInd with a central carina extending- nearly to tip; very coarsely rugulose either side of furrow with a I'dint grranulation between raised lines; pronotal spot laIrge, plaily seeni from1 aIboNve anid two spots together occupying about oine-tllirl of the dorsal aspect of' the foreborder of the pronotuim. Antenna, with wAell separated joints; fuanicle Joints 2, 3, 4, and 5 equal in length ind widlth: Joint 1 a little longer; ,Joint 5 ais well separated fr-om (dub as ftoinl ~eeigJoint; club a little longer than 4 and 5 together but of* the same widthi. XAoinen as ]lng as thorax; joint 4 shorter- than 6; 5 longer than 6: 7 aind S subequal. Color black, except for pronlotal Spot aInd ku-iees. which ar-e luteouis; claw of stiginal cluib giveui off about aIt tip of* clb, strighi.1t.
i11lc.-Length, :2.2 iml.; expanse, 4.2 imm. Petiole about as long as hind coxit and iwarly equail inl length to first abdominal segment. .Anltennas with fitmicle joints very slightly arched abov-e, eache joint fullythree times as long a s wide and slightly constricted inl middle; otherwiseI as,. With I. iwrlc-i.
Described fromn 2 teiales and I wale in the F'itch collection, labeled inl Fitch's handwvriting" Fury Iomo hordlei I arris, Nos. 153and119.


Genus ISOSOMORPHA Ashmead.

Isosomorpha mulilenbergise ni. sp.
IF/jt~le -Length, 2.2 inn.; expanse, 4.$ mmii. Tbora,,x with close faint iiimbiicate-punctaite scu11l1turin1g; metanlotil within a straight central complete gioeand a ventral carinai ini(licatted aniter~iorly-groove, however, nlot eniarlglinate; enitire thor-ax with a (dose and very short white pile except in mietaiiotal groove, which is naked. Abdomen shorter thian thor-ax, flattened from11 sides; joint 41 very longw, longer than all the rest together,; joints 2 and 3 subequA; joints 5 aind 6 very Short; joints 2. 3,) 4, alnd 5 o f itenil fuin ice, equal inl length (and width, subquatdrate; joint I longer, twice as long as pedicel; club long, ovate, a little longer thian funiclejoints 4 and 5 together. Color black1C.; front coxaw dark brownie, black ait base ;- all legrs hioney-yellow; scape slightly yellowish at base; wings hyahine: stig-inal c,]lb very small; claw feeble.
Described from one fei.male specimnen r-eared froin a gall oi ]Jluhlenberyia dif'w a, closely resembling deformation made by Tsosomta Itordei, and colce MY2, 1,1 by J. GA. B3arlow, at Cadet, Mo.





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Genus EURYTOMOCHARIS Ashmead.

Eurytomocharis eragrostidis n. sp. (fig. 8).
Female.-Leugth, 1.8 mm; expanse, 4 mm. Head and thorax very faintly shagreened, with minute umbilicate punctures on pronotum and larger ones on mesoscutellum; minetanotun with central longitudinal suture complete, but not emarginate. Abdomen shorter than thorax; joint 4 as long as 2 and 3 together; 2 and 3 subequal; 5 and 6 short. Antenne with globose funicle joints; joint 1 of funicle a little longer than pedicel, others subequal; club ovate, a little longer than funiclejoints 4 and 5 together. All legs. including coxe, dark yellow brown.
lale.-Length, 1.2 mm; expanse. 2.6 mm. Petiole faintly sculptured, as long as hind coxa; antenme with the 5 funicle joints strongly arched above and pedicellate; the body of each joint nearly as wide as

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FuI. 8.-,Eutj(,iochari eragioefifis How ard.
long; scape broad, slightly widened below; pedicel globose; club as long as two preceding funicle joints together, not obviously divided.
Described from very many male and female specimens reared Septeminber, 1885, and Marbch, 1886, from stems of Eragrostis poroides, collected at Lafayette, Ind., by F. M. Webster. The infested grass stem is as a general thing not at all or very slightly swollen. The larva excavates it for a distance of an inch or more and issues from a round hole. The first or second joint below the head seems to be the portion of the grass most commonly attacked.
Eurytomocharis triodise nii. sp.
Fenude.-Length, 3.2 nin.; expause, 5 mm. Resembles closely the foregoing species, except that it is considerably larger. Head, pronbtum, and mesonotum coarsely umbilicate-punctate; metanotum with very shallow emarginate central furrow with transverse rugosities





22

throughout its full extent; the narrow expanse either side of furrow granulate; remainder of metanotum coarsely rugose. Abdomen as ling as head and thorax together; fourth segment longer than second and third together; third twice as long as second; fifth equal in length to second. Entire thorax with close white pile. Antennme about as with preceding species, except that joint 1 of funicle is longer than 2 and nearly twice as long as pedicel; club of stigmal vein triangular; claw not distinctly differentiated. Color, black; scape, honey-yellow; all legs brown, lighter at joints: femora and tibia, dark in the middle. All coxw shagreened.
Male.-Lengtli, 2.1 mm.; expanse, 3.2 num. Petiole slightly rugose; distinctly longer than hind cox:v; antenna as with preceding species, except that joint I of the finicle is longer than 2, and 2 is longer than 3, while club is not so long as two preceding joints together.
Described from 8 females and 1 male reared April 27 and May 17, 1888, from the dry stems of Trilodia cuprea collected on the Virginia side of the IPotomac River. near Washliington, D. C., by Theodore Pergande.








I





Fu~. .- E'e Omyso f ba ritis (Sanuders).

Genus EVOXYSONA Ashmead.

Evoxysoma vitis (Saunders) (fig. 9).
Isosoma vitis, Saunders, Can. Entom. 1870, vol. 1, p. 26.
Female.-Length, 3 mm.; expanse, 5.6 mn. Head, pronotum, and mesonotum closely and rather faintly umbilicate-punctate; metanotum with a broad central longitudinal depression with convex sides, delicately shagreened in center; mesopleura below tegulh delicately shagreened; all coxe also shagreened. Abdomen as long as head and thorax together; joint 4 as long as 2, 3, and 5 together; 2, 3, 5, and 6 subequal. Antenue submoniliform; funicle joints 1 and 2 nearly equal in length, 1 slightly longer; remaining joints decreasing in length very slightly; club nearly equal to three preceding joints together; head and







thorax with close, fine, white pile, which is also present on terminal joints of abdomen. Color black, anitennal scape yellowish; all coxte black, the front pair somewhat yellowish at tip; front and middle legs except coxe honey-yellow; hind femora brown in middle, honey-yellow at either end; hind tibiae honey-yellow, slightly brownish in middle; base of abdomen below brownish; stigmal club well rounded, claw straight and short.
Male.-Petiole thick, shagreened, longer than hind coxie, as long as first abdominal joint; antenne as with male of Eurytomocharis triodiw, except that the funiclejoints are somewhat more strongly pedicellate. All legs, excepting middle and hind coxte, honey-yellow.
Described from six females and four males apparently reared from grape seeds by C. V. Riley. The specimens are all in the old Riley collection, together with five shriveled grapes from which they have emerged. The series is probably the one referred to in the Second










1I





FIG. 10.-Decatomidea cooki Howard.
Report on the lusects of Missouri (p. 92), where it is stated that they were reared from infested grapes received in August, 1869, from A. S. Fuller, of New Jersey, and obtained by him from Canada. The evidence in favor of the phytophagic habit of the species, as given by Saunders in the Canadian Entomologist, is apparently conclusive, )ut there is still a chance that this species and the next one are parasitic or inquilinous. They hardly belong structurally to the phytophlagic group of the Eurytomina.

Genus DECATOMIDEA Ashmead.

Decatomidea cooki ni. sp. (fig. 10).
Female.-Length, 3.6 minm; expanse, 5.8 mm. Head, lpronotum, alnd mesonotum densely and rather coarsely and regularly umbilicate p)uctate; metanotum with a very broad central, slightly emarginate, and





24

very shallow shagreened furrow. Antennme rather long, moniliform; funicle joint 1 more than three times as long as pedicel and nearly three times as long as thick; joint 2 shorter than 1, twice as long as thick; joint 3 a little longer than 2; 4 and 5 each as long as 2; club as long as 4 and 5 together. Body nearly naked; pile sparse. Color black; antenna yellowish; all legs yellowish except hind coxm, which are blackish above and below; underside of thorax, all of face, including margin behind the eyes,m'and underside of abdomen, yellow, the yellow of the abdomen extending dorsally nearly to the middle on fifth and sixth segments; fourth segment as long as second and third together; fith longer than third. but shorter than fourth; second and sixth equal.
Described from one Temale specimen reared March 12,1884, from grape seeds received January 28, 1884, from A. J. Cook, at Lansing, Mich. There are four specimens in the national collection received by Professor Riley in the fall of 1886 from Dr. Franz Loew, of Vienna. The females differ from the single female reared fIrom the seed sent by Professor Cook only colorationally; the yellow is much more prevalent and the blackis reduced to a series of dorsal markings. Of the four specimens received from 1)r. Lowe, two are males and two females. The accompanying figure was drawn from one of the Loew females. With the males the antenna, are elongate, the dorsal whorls of hair on the fulnicle joints being very long, two distinct whorls to each joint, and the segment somewhat constricted between the whorls; not strongly pedicellate; joints 4 and 5 shorter than 2 and 3; club not longer than funicle joint 5. Each funicle joint is at least four times as long as broad, and the dorsal elevation is not strongly marked. In coloration the males are darker than the females. The longitudinal dorsal thoracic black band is broader behind although narrower on the pronotum, where it is supported on either side by a black d(lot. The dorsum of the abdomen is entirely black.
Dr. Loew wrote that the specimens were reared from seeds of Vitis californica. The seeds were imported from California to Vienna in the month of January. The imagos emerged from the seeds at some time between April 12 and June 15. A very great number of seeds were infested and the larve consumed the entire seed contents.
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Tech. Ser, No. 3, Div. Entom., U. S, Department of Agriculture. ~FRONTI6PIECE.



























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LEAF GALLS OF PONTANIA.

1. PorntaPa resinicola n. sp. 4. P. Pornun Walsh. 7. P. brunzeri n. sp.
2. P. hyalina 'Norton. 5. P. p~yrifurm11is n. sp.
3. P. desmodi'oides Walsh. 6. P. 711On Ie ii. sp.