﻿ON SOME SPECIES OF GALL-GNATS (cECIDOMYLe). 281 



forceps is still narrower in proportion to its length, frater being 

 thus intermediate in this respect. 



Cecidomyia alticola, n. sp. 



Gall. — Globular wool-like galls, with radiating fibres, being the aborted 

 flower-heads of a species of Oompositse. I collected thes e galls when the 

 plant had died down, and only the dead stalks were left : it seems to be a 

 Ghrysopis or Solidago. 



Larva. — Colour orange. 



Pupa-shell. — ■ Long. If mill. White, with the thoracic coverings shiny 

 grey. 



Imago. — Expanse about 4 mill. Head dark ; eyes very black ; antenna 

 brownish, moniliforrn, 16-jointed, each joint emitting some (twelve or more) 

 long white hairs ; joints diminishing in size towards tip. Thorax dark. 

 Legs brownish ; halteres large, slightly hairy, tinged with reddish. Abdomen 

 reddish or pale brown, the male genitalia much darker. Wings hyaline, 

 with a row of strong bristles on the costa, and a strong fringe on inferior 

 border. Venation simple ; second longitudinal vein straight, fading towards 

 margin, or reaching margin perhaps slightly below the apex of the wing ; 

 third longitudinal vein fading, or (in one male) curving abruptly downwards, 

 reaching inferior margin, with no anterior branch. 



Female abdomen redder than that of male ; ovipositor very 

 short. 



Male genitalia differ from those of Diplosis pyrivora as 

 follows : — In C. alticola the hairs of the first joint of the forceps 

 are longer; and the second joint of forceps is less slender and 

 less curved, being in fact quite thick. 



One male appeared to have the antennae 11 -jointed only, but 

 I am not sure that some joints had not been broken off. 



Described from fresh specimens, bred April 24th (some earlier), 

 from galls collected in 1890, at West Cliff, Colorado. 



Many Cecids have been bred by different authors from species 

 of Compositse, but the present species seems quite distinct from 

 all of them. 



Of the American species C. hirtipes, O.-S., C. solidaginis, Lw., 

 C .racemicola, O.-S., C.anthophila,O.S., and C. carbonifera, O.-S., 

 all on Solidago, make quite different galls from alticola. C. an- 

 thophila, which might possibly be confused with our species as 

 to its gall, has also a quite different fly, with pale brown thorax 

 and twenty-one antennal joints. C. chrysopsidis, Lw., makes a 

 gall on Chrysopsis mariana which seems to be exceedingly like 

 that of alticola, but the imago is different. There are also 

 American species of Asphondylia and Lasioptera on Composite, 

 but these need not be considered. 



The European C. obfuscata, Mg., is said to have brown bands 

 on the tibise and tarsi, but otherwise the imago seems a good deal 

 like alticola, though it has a different life -history. C. floricola, 

 Winn., is also rather like our species, but differs in a few points, 

 besides breeding in Achillea. The recently described C. florum, 

 Kieffer (Ent. Nach. 1890, p. 37), is evidently distinct; it feeds on 



