fttE CANADIAN BiNTOMOLOGlST. 89 



A NEW GALL ON ASTER. 



BY T. D. A. COCKERELL, BOULDER, COLO. 



Early in October, 1907, I collected a quantity of Aster crassulus^ 

 Rydberg, in Boulder, for the use of the biology class of the preparatory 

 school. A student, Milton Bergheim, observed that it carried galls, which 

 I had inexcusably overlooked. Once noticed, it was easy to find more ; 

 in fact, the plants swarmed with them. On opening them the flies were 

 found to be in the pupa stage, and so were easily bred out a few days 

 later. The species is undescribed. 



Cecidomyia crassulina, n. sp. 



^. — Length, 1^3 mm.; of wing, i^ mm.; middle legs a little over 

 3 mm.; head small, transverse diameter about 357 /x, eyes meeting on 

 vertex. Reddish-brown, the abdomen paler and grayer, the sides of the 

 thorax orange ; legs and antennae pale gray-brown ; halteres orange. 

 Antennae moniliform, with [9 (2 + 17) joints, these with whorls of hairs 

 about 204 1^ long. -Wings very hairy ; hairs on lower margin about 170 /x 

 long: first vein (R^) about 1360 // long; second (R2+3) reaching tip of wing ; 

 third (cubitus) distinct only as far as the fork, which is almost exactly 

 half way between base and apex of wing. Claws strongly curved, simple. 

 Claspers with apical joint finger-like, strongly curved, obtuse, thickened 

 at end. - 



Measurements of legs in /x : 



Anterior legs : femur, 108S ; tibia, 1207. 



Middle legs: femur, 10S8; tibia, 1071; tarsal joints, (i) 85; (2) 

 867; (3) 374; (4) 204; (5) 102. 



The antennre are much like those oi Dasyneura pseudacacice, except 

 as to the number of joints, but the venation is quite different, the second 

 longitudinal being curved and ending much lower down. The terminal 

 joint of the claspers is something like that of C. salicis-batatas (Ckll., 

 Entomologist, 1890, p. 278), but much more curved and thickened at 

 end. It is more like that of Diplosis violicola, Coq. The flies emerged 

 October 1 1. 



The galls are sessile on the branches, often two placed side by side. 

 They are short-oval, about 7 mm. long, densely covered with white hair, 

 looking something like small green peaches. 



March, 190S 



