THE CANADIAN ENTOMOLOGIST. 217 



A NEW OAK-GALL. 



BY T. D. A. COCKERELL, EAST LA.S VEGAS, N. MEX. 



DryopJianta rydbergiana, n. sp, — Gall: on leaf of Querais rydber- 

 gia7ia, Ckll. (Torreya, Jan., 1903) ; solitary, 6 mm. diameter, spherical, 

 faintly shiny, light ferruginous, with a microscopically tessellate surface and 

 a scattered stellate pubescence ; base concave, point of attachment small; 

 contains a single large cell ; the space between the cell and the exterior 

 filled with spongy tissue, which is light green within and ferruginous out- 

 wardly. 



Fly (cut from gall): 9. — Body 2}^ mm. long, stout, jet black, 

 smooth, neither punctured nor conspicuously hairy ; mesothorax and 

 scutellum with a few scattered hairs ; front and vertex minutely tessellate ; 

 no frontal groove ; middle ocellus somewhat depressed ; face without 

 carinae; malar space long, wrinkled; flagellum black, 12-jointed, the last 

 five joints (at least) longitudinally grooved; whole flagellum hairy; first 

 flagellar joint about one-fourth longer than second ; basal joints of 

 antennse dark red ; the small first joint punctate ; the second much 

 swollen. Parapsidal grooves deep and strong, complete, converging 

 posteriorly ; scutellum large and swollen, longitudinally keeled, with a 

 depression on each side anteriorly ; anterior margin of scutellum raised 

 into a sharp edge ; posterior part coarsely cancellate. jNIetathoracic 

 ridges very widely divergent caudad. Legs red ; tarsi hairy ; claws of 

 posterior legs simple; wings hyaline, not spotted, but hairy; veins 

 strongly marked with dark brown; marginal vein not quite attaining costa; 

 areolet present. Ovipositor black, concealed ; ventral spine red, covered 

 with long ferruginous hairs. 



Hab. — Las Vegas Hot Springs, N. M., about 7,000 feet, March 21, 

 1903. The gall was on a leaf of last year, the leaves of Q. rydbergia/ia 

 remaining on the bush, though turning brown. 



This insect is placed in Diyoplumta, because it seems on the whole 

 to go there best, but it does not exactly agree with any described Ameri- 

 can genus. In Mayr's table, given by Cresson, it runs to Biorhiza, but it 

 does not belong there. The gall is like that of Amphibolips. 



