404 NEW YORK STATE MUSEUM 



d Fifth antennal segment with the stems subequal, each with a length 

 2^ and 3>< times the diameter ; abdomen yellowish brown, length 



I mm (Cecidomyia) filicis Felt, C. 139, 538 



cc Dorsal plate short, broadly and triangularly emarginate 



d Fifth antennal segment with the stems equal, each with a length 



2H times the diameter; abdomen dark red, length i mm 



(Cecidomyia) fraxini Felt, C. 179 

 bbb Ventral plate rather short, broad 



c Dorsal plate rather long, broad, deeply and triangularly emarginate 

 d Basal clasp segment with a rounded lobe basally ; abdomen yellowish 

 brown, length i mm. .(Cecidomyia) acerina Felt, C. 149 

 dd Basal clasp segment without a basal lobe internally ; abdomen light 



yellowish brown, length i mm fenestra n. sp., C. 641 



cc Dorsal plate rather long, narrowly incised 



d Abdomen fuscous, length .75 mm o b s c u r a n. sp., C. 399 



bbbb Ventral plate rather short, narrow, .narrowly rounded apically 

 c Dorsal plate short, broadly and triangularly emarginate 



d Fifth antennal segment having the basal portion of the stem with 

 a length ^ its diameter or less 

 e Abdomen yellowish or dark carmine, length i mm ; third palpal 



segment slender iapiphila Felt, C. ai775, 524 



ee Abdomen reddish brown, length i mm ; third palpal segment 

 broadly oval. ..(Cecidomyia) macrofila Felt, C. 1023 

 aa Ventral plate truncate 



b Dorsal plate short, deeply and triangularly incised ; abdomen pale 

 yellowish, length .5 mm; bred from heads of curled sumac leaves. ... 



r h o i n a n. sp., C. ai72ob 



bb Dorsal plate very short, deeply and narrowly emarginate, length i mm; 



bred from rolled elder leaves. . .s a mb u c i f o 1 i a n. sp., C. 31723 



ODONTODIPLOSIS n. g. 



This genus is erected for the separation of certain species allied 

 to Cecidomyia, which may be distinguished therefrom by the triartic- 

 ulate palpi and the conspicuous serrations on the somewhat conical 

 ventral plate or harpes. 



Type Cecidomyia karnerensis Felt, C. 27. 



Key to species 



a Fifth antennal segment having the basal portion of the stem with a length 

 about >4 greater than its diameter 

 b Length .75 mm ; abdomen reddish yellow 



(Cecidomyia) karnerensis Felt, C. 27 

 aa Fifth antennal segment having the basal portion of the stem with a length 

 2^ or 3 times that of the diameter 



/; A1)(lomcn i)alc orange a m c r i c a n a n. sp., C. 451, 660 



bb Abdomen fuscous yellowish m o n t a n a n. sp., C. 718 



