212 NEW YORK STATE MUSEUM 



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

 both ends. 



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

 thickly haired, yello^^ish bro\\Ti; 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. IMesonotum dark brown, the sub- 

 median lines thickly haired. Scutellum yellowish brown, darker 

 basally, postscutellum yello'v\ish bro-^m. Abdomen sparsely clothed 

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

 yello^^ish. Wings hyaline, costa pale straw. Halteres yello-^dsh 

 basally, fuscous apically. Coxae, femora and tibiae pale 3^ellowish, 

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

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

 trtmcate; 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, sparsety haired, fuscous yellowdsh; 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. 0\dpositor 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 Sa}^ ' 



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

 (Mayetiola) 



1902 Felt, E. P. N. Y. State jMus. 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 that it lives in an important cereal 



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

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

 extensive bibUographies. 



