228 ■ NEW YORK STATE MUSEUM 



griseola. Several species have been reared from American j 

 specimens and found to be different from the old world enemies. 



Oligotrophus vernalis Felt 



1908 Felt, E. P. N. Y. State Mus. Bui. 124, p. 368 



The female was taken on basswood, Tilia americana, 

 Kamer, N. Y., May 19, 1906. 



Female. Length 1.5 mm. Antennae about as long as the body, §1 

 sparsely haired, reddish brown; 14 segments, the fifth with a stem 

 about one-fourth the length of the basal enlargement, which latter 

 is distinctly rounded basally and apically; terminal segment slightly 

 prolonged, subovoid, with a distinct subcorneal knob apically. 

 Palpi; the first segment subquadrate, stout, the second suboval, a 

 little longer than the first, the third longer than the preceding, rather 

 stout. Mesonotum dark brown, submedian lines ornamented with 

 setae. Scutellum yellowish, thickly clothed apically with dark 

 setae, postscutellum yellowish, ferruginous. Abdomen dark brown, 

 tinged with reddish. Wings hyaline, costa reddish brown; halteres 

 reddish transparent. Coxae and femora yellowish red, tibiae and 

 tarsi variable reddish brown and yellow; claws stout, uniformly 

 curved. Ovipositor nearly as long as the abdomen, terminal lobe 

 rather slender, narrowly rounded. Type Cecid. 606. 



Oligotrophus salicifolius Felt 



19 10 Felt, E, P. Econ. Ent. Jour., 3: 354 



The irregular, yellowish, red-spotted galls of this species on the 

 leaves of Salix humilis were taken at Kamer September 7, 

 1909, adults being reared in March and April of the following year. 

 The deep orange larvae appear to desert the galls in late fall, spin- 

 ning oval, yellowish cocoons attached to any hard substance such as 

 a leaf. The gall is very similar to that of O. capreae Winn, 

 and the adults are evidently closely allied though separable in color 

 chsiracteristics. 



Gall., Length 2 to 3 mm, irregular, ovoid, monothalamous, 

 yellowish, red-spotted and usually most evident on the under surface 

 of the leaves of Salix humilis. 



Larva. Length 1.75 mm, rather stout, deep orange. Head small; 

 breastbone rudimentary or wanting; skin roughly shagreened; 

 posterior extremity broadly rounded, slightly lobed. 



Cocoon. Length 1.75 mm, white, narrowly oval, somewhat 

 irregular and attached to a dead leaf. 



Exuviae. Length 1.25 mm, whitish transparent; thoracic spines 

 stout, slightly curved; antennal cases extending to the second 



