﻿ON SOME SPECIES OP GALL-GNATS (CECIDOMYIiE). 279 



and red like the twigs on which they grow ; they appear to have their origin 

 in aborted buds ; they contain a single cavity. 



Larva. — Long. 4, lat. 1{ rum. Subcylindrical, bright orange, tinged with 

 crimson above. (Extracted from gall Jan 27th, 1890.) 



Pupa-shell. — Larger than that of C. s-hatatas. Coverings of antennae, 

 legs and wings grey, in striking contrast to the white abdomen. 



Imago. — Long. 4 i, al. exp. 9 mm. ? . Antennas 20-jointed. 



The above description refers to the species found at West 

 Cliff, Colorado, which I have hitherto called C. s-siliqua. It is 

 very probably identical with Walsh's species, but on the whole it 

 agrees better with rigidce, as described by Fitch. Walsh describes 

 salicis-siliqua as having the origin of the anterior branch of the 

 third longitudinal vein pretty distinct, which is not the case with 

 my species, but Walsh admits s-siliqua to be variable in this 

 respect. 



The West Cliff species has the thorax dull black, with rather 

 coarse pale hairs at the sides ; halteres brownish ; abdomen dull 

 dark brown or brown-black, clothed at sides and beneath with 

 white hairs. Legs grey-brown, pink at joints ; wings hyaline, 

 veins brown. These notes are from fresh specimens, which 

 emerged from the galls in May, 1890. Fitch's species is said to 

 have the tarsi black, and the wings smoky brown. 



I think the Colorado species may be safely referred to rigidce. 

 and Walsh's salicis-saliqua (a later name) to a variety of the same 

 species. Still it is possible that Walsh's insect may be distinct. 



Cecidomyia salicis-batatas, Walsh, 1864. 

 ? = spongivora, Barnst. MS., Walker, 1848. 



Gall. — A large, irregularly oval gall, at the end of a willow twig. 



Pupa-shell. — Almost entirely white. 



Imago. — $ . Long. 2^ al. exp. 6 mm. Wings hyaline, pale greyish ; third 

 longitudinal vein very indistinct beyond the branch, or sometimes more 

 distinct ; second longitudinal vein conspicuous, and a lively brown, whereas 

 the other veins are dark grey or black. Antennae apparently 17-jointed. 

 Thorax dark reddish brown, with subdorsal longitudinal lines of pale hairs ; 

 halteres greyish, pale at tips. Abdomen dark brown, the segments very 

 distinct, covered with white hairs except at sutures beneath, and above the 

 lower edge of each segment strongly fringed with long white hairs. Legs 

 brown, pale at joints. (Described from fresh specimens.) 



Hab. West Cliff, Custer Co., Colorado. Emerged from gall 

 May 21st, 1889. 



I have no doubt that the above species belongs with Walsh's 

 s-hatatas, although Walsh thought, " unless his memory failed 

 him," that the male abdomen of his species was luteous when 

 recent. 



As to spongivora, so far as the description goes, it might well 

 be this species. I have examined the types of spongivora, 

 Barnst. MS., in the British Museum, and they agree in size and 

 general appearance with the Colorado s-batatas. The thorax is 

 dark, but the legs are rather paler than in the Colorado form : 



