Diastrophus nebulosus

Diastrophus turgidus

Diastrophus kincaidii

Diastrophus radicum

Diastrophus bassettii

Diastrophus cuscutaeformis

Diastrophus fusiformans

Diastrophus niger

Aprostocetus smilax

Diastrophus potentillae

Diastrophus nebulosus (Osten Sacken)


Cynips (Diastrophus ?) nebulosus OSTEN SACKEN
Diastrophus nebulosus OSTEN SACKEN

Gall. (Plate XXVI, Figs. 1,2.) On stems of blackberry (Rubus villosus). Very variable in shape and size. Round, elongated, or irregular, sometimes with deep longitudinal furrows which divide the gall more or less completely into four or five parts. Dark green, tuirning reddish as the season advances. Hard, corky or pithy inside with many larval cells. Length 25-75 mm. and diameter about 25-40 mm. 

Habitat: Canada (Ontario); New England and Middle States; D. C.; Maryland; Delaware; Virginia; North Carolina, south to Florida; Ohio; Illinois; Indiana; Missouri; Iowa; Wisconsin; Michigan; Oklahoma; Colorado. Very common and widely distributed. The galls are usually very common and are very irregular in size and shape. The types are in the Museum of Comparative Zoology, Cambridge, Mass.

Diastrophus turgidus Bassett.

Diastrophus turdigus BASSETT
Diastrophus turgidus ASHMEAD
Rhodites radicum RILEY

Gall. (Plate XXVI, Figs. 3, 4, 5, 6, 7, 8, 9; Plate XXVII, Fig. 1). On the stalk of wild red raspberry (Rubus strigosus) and probably allied species. Polythalamous. Abrupt pithy swellings surrounding the stem. Irregular in shape, smooth or more or less covered with short spines. Length 25 to 75 mm.; width 15 to 30 mm. 

Habitat: Canada (Ontario); New England States to Massachusetts; Ohio; Colorado. 

The adult of D. turgidus somewhat resembles that of D. nebulosus. It differs in having the parapsidal grooves not so widely separated as in nebulosus, and the face less coarsely aciculate. It is also as a rule darker in color. Turgidus is hardly distinct from nebulosus, and may ultimately prove to be the same. The types are in the American Museum of Natural History and American Entomological Society. 

Diastrophus kincaidi Gillette

Gall. (Plate XXVII, Figs. 2, 3). On the stalk of blackberry (Rubus nutkanus). Polythalamous. Abrupt enlargements surrounding the stalk, very much resembling the galls of Diastrophus turgidus, externally. Inside they are literally filled with hard larval cells, which are divided by thin hard partitions and a thin layer of soft pithy substance forms the external portion of the gall. Length 25 to 60 mm.; diameter 12 to 25 mm. 

Habitat: California (Alameda Co.); Washington (Olympia; Seattle); Idaho (Cedar Mts.). 

This species is allied to D. turgidus but is abundantly distinct. It may be easily known by the rugose scutellum and the median groove on the mesothorax. The gall differs from that of D. turgidus by being filled with hard, oval, larval chambers. The types are with Prof. C. P. Gillette. The galls on Plate XXVII, Figs. 2 and 3, I received from Mr. A. L. Melander. 

Diastrophus radicum Bassett

Diastrophus radicum BASSETT
Rhodites radicum GILLETTE

Gall. (Plate XXVII, Figs. 4, 5). On the roots of running blackberry or dewberry (Rubus canadensis), and probably allied species. Polythalamous. Brown, pithy and irregular in shape, varying in size from the shape of a pea of two inches or more in length and nearly an inch in diameter. Sometimes the entire root stalk above and below the surface of the ground, is surrounded by almost a solid mass of galls, measuring about three inches in diameter. 

Habitat: Canada to North Carolina; Michigan, Colorado. 

The fly is allied to D. turgidus, but may be readily separated by the absence of the brown color of the radial vein before reaching the second cross-vein. I have taken galls on the roots of the black raspberry or blackcaps (Rubus occidentalis) which may prove to be the same as D. radicum. According to Bassett the galls also may be found on the roots of the high bush blackberry (Rubus villosus). The types are in the American Museum of Natural History and American Entomological Society. 

Diastrophus bassetti Beutenmuller

Gall. (Plate XXVIII, Figs. 1, 2, 3, 4, 5). On the stems at the roots, or partly below the surface of the ground, on trailing blackberry (Rubus canadensis) and probably allied species. Polythalamous. Irregularly rounded or somewhat elongated or almost globular in shape. Composed of a fleshy substance when fresh and pithy when dry and mature. Greenish or yellowish green, tinged with red or sometimes almost entirely red. Diameter from 12 to about 25 mm. 

Habitat. New York; New Jersey; Connecticut; Massachusetts; Rhode Island; North Carolina (Black Mts.). 

The adult may be known from its congeners by the strong aciculations and the fine linear elevation on the face, the aciculations on the mesothorax, and dark rufous legs and antennae. It is allied to D. radicum. The gall is sometimes quite common locally, reaching maturity late in autumn. The types are in the American Museum of Natural History and American Entomological Society. 

Diastrophus cuscutaeformis Osten Sacken

Gonaspis cuscutaeformis 

Gall. (Plate XXVIII, Figs. 7, 8, 9, 10). On stalk of blackberry (Rubus villosus, R. canadensis and R. cuneifolium). Monothalamous. Consists of numerous small, globular, woody, seed-like bodies, pressed closely together, each provided more or less with spines or filament. Dark green, turning red as the season advances. 

Habitat: Canada (Ontario); New England and Middle States; probably southward to Florida; Illinois; Ohio; Michigan; Iowa; Missouri; Indiana. 

The gall is sometimes quite common locally and several hundred are often on a single stalk. It may be readily known by the seed-like bodies, each containing a single larva. Dalla Torre and Kieffer erroneously refer D. cuscuteformis to the genus Gonaspis of Ashmead. The types are in the Museum of Comparative Zo6logy, Cambridge, Mass. 

Diastrophus fusiformans Ashmead

Gall. (Plate XXIX, Figs. 15, 16.) On the stems of Potentilla. Polythalamous. An elongate, fusiform swelling, sometimes curved, or otherwise deformed. Length 15 to 45 mm. Diameter 5 to 8 mm. 

Habitat: Colorado (West Cliff: T. D. A. Cockerell); Washington (Pullman); Garrison, New York (T. D. A. Cockerell); Massachusetts, Miss Cora H. Clark. 

This species is unknown to me and Ashmead's description of the adult is here reproduced. The galls occur on different kinds of Potentilla. Prof. T. D. A. Cockerell collected a gall on this plant at Garrison on the Hudson, New York, which in appearance is the same as D. fusiformans, and Miss Cora H. Clark sent me fusiform swellings on Potentilla canadensis which may also prove to be D. fusiformans when the adults are bred from them. The records New York and Massachusetts, therefore are doubtful. The types are in the United States National Museum. 

Diastrophus niger Bassett

Diastrophus minimus BASSETT

Gall. (Plate XXIX, Figs. 4-13). On the stems, or midribs of the leaves of Potentilla canadensis. Monothalamous when single and polythalmous when in numbers. Round, oval or elongate, smooth swellings (Fig. 6) sometimes involving the whole stem. Sometimes in nodules, singly, (Fig. 11) or in numbers, especially when on the midribs (Figs. 13, 14). Green when fresh and brown and pithy when dry. 

Habitat: New York; New Jersey; Connecticut; Rhode Island; Massachusetts. 

This species will probably be found everywhere locally, within the distribution of its host plant (Potentilla canadensis), which is distributed from Canada to Georgia and to Minnesota and Indian Territory. Through the kindness of Miss Cora H. Clark I received a number of galls on the midribs of the leaves and upon the stems, from which I raised many examples of the adults of D. niger. D. minimus I cannot separate from D. niger. This was bred by Bassett from blister-like galls which he supposed to be distinct from the double or confluent galls of D. niger. The types of niger and minimus are in the American Museum of Natural History and the American Entomological Society.

Diastrophus smilacis Ashmead

Gall. (Plate XXVIII, Fig. 6). On stems of smilax (Smilax rotundifolia, S. herbacea and S. havanensis). Polythalamous. Irregularly rounded, abrupt, swellings usually surrounding the stems, sometimes resembling the gall of Rhodites globuloides. Green when fresh and of a pithy structure. Diameter 16 imm. 

Habitat: Illinois; Florida. 

The type galls of this distinct species sometimes resemble those of the rose gall, Rhodites globuloidees Beut. Figure 6 on Plate XXVIII was made from a gall found on Smilax havanensis collected by Dr. E. Bessey at Miami, Florida. The types of D. smilacis are in the United States National Museum, and one female cotype in the American Museum of Natural History. 

Gonaspis potentillae Bassett

Diastrophus potentillae BASSETT

Gonaspis potentillae var. scutellaris GILLETTE.

Diastrophus scutellaris GILLETTE
Gonaspis scutellaris ASHMEAD

Gall. (Plate XXIX, Figs. 1, 2, 3). On the axils of leaves of Potentilla canadensis. Monothalamous. Spherical or oblong, usually pointed at the base. Green in summer and brown, pithy in winter. Inside it is soft, spongy and contains an oval, hard, larval cell. Diameter 8 to 12 mm. 

Habitat: Ontario, Nova Scotia, Canada; New England States; Middle States; Ohio; Illinois. I have bred Gonaspis scutellaris, which is nothing more than a variety of G. potentillae. I have bred scutellaris from galls identical with those of potentillae. The types of potentilla are in the American Museum of Natural History and the American Entomological Society. The type of scutellaris is in the Laboratory of Natural History at Urbana, Illinois. 

The North American Species of Diastrophus and their Galls