212 NEW YORK STATE MUSEUM 



Gall. A very elongate, slender swelling of the twig, tapering at 

 both ends. 



Male. Length 1.5 mm. Antennae nearly as long as the body, 

 thickly haired, yellowish brown; 17 segments, the fifth with a stem 

 three-fourths the length of the basal enlargement, which latter 

 has a length one-half greater than its diameter; terminal segment 

 produced, tapering, acute. Palpi; first segment short, subquadrate, 

 the second quadrate, with a length one-half greater than its diameter, 

 the third a little longer, more slender, the fourth one-half longer 

 than the third, more slender. Mesonotum dark brown, the sub- 

 median lines thickly haired. Scutellum yellowish brown, darker 

 basally, postscutellum yellowish brown. Abdomen sparsely clothed 

 with silvery hairs, dark brown (dark red in life). Genitalia fuscous 

 yellowish. Wings hyaline, costa pale straw. Halteres yellowish 

 basally, fuscous apically. Coxae, femora and tibiae pale yellowish, 

 the tarsi slightly darker; claws long, slender, evenly curved, the pul- 

 villi as long as the claws. Genitalia; basal clasp segment long, 

 truncate; terminal clasp segment long, tapering; dorsal plate broad, 

 deeply and triangularly incised; ventral plate short, deeply and 

 roundly emarginate. Harpes long, stout, obliquely truncate. 



Female. Length 2 mm. Antennae extending to the second 

 abdominal segment, sparsely haired, fuscous yellowish; probably 

 17 segments, the fifth subsessile, with a length two and one-half 

 times its diameter; subbasal whorl thick ; short, subapical band 

 rather scattering, relatively short. Ovipositor about one-half the 

 length of the abdomen, the terminal lobe with a length three times 

 its width, broadly rounded. Type Cecid. 920. 



Phytophaga destructor Say * 



Hessian fly 



1817 Say, Thomas. Acad. Nat. Sci. Jour., 1:45-48; same republished in 

 Le Conte Say's Complete writings, 2: 4-6, 1883 (Cecidomyia) 



1847 Fitch, Asa. N. Y. State Agric. Soc. Trans., 6:316-73 (same, separate 

 date 1847, p. 3-60, Cecidomyia) 



1883 Packard, A. S. U. S. Ent. Com. 3d Rep't, 1883, p. 198-248 (Cecid- 

 omyia) 



1897 Marchal, Paul. Soc. Ent. de Fr. Ann., 66: 1-42, 43-47, 51-62, 80-100 

 (Mayetiola) 



1898 Osborn, Herbert. U. S. Dep't Agric. Div. Ent. Bui. 16, n. s., p. 1-57 

 (Mayetiola) 



1902 Felt, E. P. N. Y. State Mus. Bui. 53; Rep't for 1901, p. 705-30 

 (Mayetiola) 



1909 Hayhurst, Paul. Econ. Ent. Jour., 2: 231 -34 (Mayetiola) 



The Hessian fly is one of the best known representatives of the 

 gall midges, owing to the fact thai it Lives in an important cereal 



1 An extended economic bibliography is purposely omitted since so much of it 



is a repetition Oi well-known citations. The later publications cited below have 



extensive bibliographies. 



