REPORT OF THE STATE ENTOMOLOGIST I913 9I 



Rhabdophaga nodula Walsh 



1864 Walsh, B. D. Ent. Soc. Phil. Proc, 3:599 (Cecidomyia) 

 1906 Felt, E. P. Ins. Affect. Prk. & Wdld. Trees, N. Y. State Mus. 

 Mem. 8, 2 745 

 1908 N. Y. State Mus. Bui. 124, p. 351, 352 



1908 Jarvis, T. D. Ent. Soc. Ont. 38th Rep't, p. 87 



1909 Ent. Soc. Ont. 39th Rep't, p. 92 



This gall was recorded by Walsh as being rare on S a 1 i x 

 1 o n gi f o li a near Rock Island, 111. It is somewhat common in 

 the vicinity of New Y^ork City, though it does not appear to be 

 abundant around Albany. The insects winter in the gall, appearing 

 in early spring. A circular gallery is first excavated nearly to the 

 surface, leaving only a thin piece of bark attached by a few fibers 

 here and there, which is readily pushed aside by the pupa as it 

 emerges, the empty exuvium being left partly extruded. P 1 a t y- 

 gaster obscuripennis Ashm. and Polygnotus species have 

 been reared from this gall. 



Gall. The gall of this species is a small, nodular swelling, usually 

 encircling the base of the smaller branches. See plate 8, figure i 

 and plate 12. 



Male. Length 2.5 mm. Antennae extending to the fourth ab- 

 dominal segment, fuscous brown ; 16 segments, the fifth with a 

 stem three-fourths the length of the subcylindric basal enlargement, 

 which latter tapers slightly at each extremity; terminal segment 

 prolonged, narrowly oval, irregularly rounded apically. Palpi ; the 

 first segment long, slightly swollen distally, the second shorter than 

 the first, stout, irregularly subquadrate, the third a little longer 

 than the second, more slender, slightly swollen distally, the fourth 

 as long as the third, flattened, broader ; face and mouth parts 

 fuscous. jMesonotum dark brown, submedian lines thickly clothed 

 with rather long, fuscous setae. Scutellum dark brown with numer- 

 ous apical setae, postscutellum orange. Abdomen dark brown, the 

 segments rather thickly margined posteriorly with long, fuscotis 

 hairs ; genitalia dark brown. Wings hyaline, costa with the basal 

 half black, the distal portion reddish. Halteres yellowish basally, 

 fuscous apically. Legs a nearly uniform dark brown ; claws long, 

 slender, slightly curved, the pulvilli as long as the claws. Genitalia ; 

 basal clasp segment short, stout ; terminal clasp segment stout at 

 base, obtuse ; dorsal plate broad, long, deeply and triangularly in- 

 cised ; ventral plate broad, deeply and triangularly incised. Harpes 

 broad, tapering, broadly rounded or subtruncate. 



Female. Length 3.5 mm. Antennae extending to the second 

 abdominal segment, sparsely haired, dusky yellowish, apical seg- 

 ments reddish; 15 segments, subsessile, tapering; the fifth with a 



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