166 Descriptions of British Diptera. 
transmitted to him by Dr Leach, which was taken in England, pro- 
bably in Devonshire, There seems reason to suppose that it is only 
a variety of C. polita, as that species evidently varies considerably, 
and in ordinary specimens the base of the antennae are frequently 
yellow. In an example of C. flavicornis taken last summer in Rox- 
burghshire, the legs are entirely pale-yellow, the hinder thighs 
scarcely tinged with brown. If carefully sought after it will pro- 
bably be found not to be rare. 
" Once taken at Dover," Curtis, B. E. vii. fol. 305. " Dumfries- 
shire," Sir W. Jardine, Bart. " Common in Ireland, along with 
C. polita" A. H. Holiday, Esq. 
GENUS PACHYGASTER, Meig. 
Antennae small, approximating at the base, turned obliquely out- 
wards anteriorly, the radical joint minute, the second larger and 
transverse, the third large and spherical, 'divided into four very 
indistinct rings, and having a slightly pubescent seta attached to the 
outer side near the extremity, (Fig. 1 ;) palpi inserted at the base 
of the maxillae, very minute, (Fig. 2, a ;) labrum robust and cylin- 
dric, the apex ob- 
tuse and slight- 
Iynotched,(Fig. 
2, b ;) tongue 
about half the 
length of the la- 
brum, horny, and 
attenuated from the base to the apex, (Fig. 2, c ;) maxilla long, 
slender, and acute, (Fig. 2, d ;) eyes approximating in the males ; 
ocelli three ; thorax with a transverse suture ; scutellum without 
spines ; abdomen much wider than the thorax, subglobose ; halteres 
large and ovate. 
This genus was constituted by Meigen, and is synonymous with 
that named Vappo by Fabricius and Latreille. It includes only two 
species, one of which does not appear to be known to continental 
naturalists. They are both minute insects, of obscure colours, and 
frequent woods and gardens. The larva of P. ater is described by 
Macquart as elongated, of a reddish-grey colour, and marked with 
three obscure longitudinal bands. 
1. PACHYGASTER ATER. 
Vappo ater, Fabr. Latr. Sargus pachygaster, Fallen. Nemotelus ater, Pan- 
zer, liv. fig. 5 ; Meig. ZweL iii. 102, pi. 24, fig. 17. 
Body black, smooth and shining, marked with minute punctures; 
