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 Jlavicornis 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. Haliday, 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 j) labrum robust and cylin- 

 drical^ apex ob- 

 tuse and slight- 

 ly notched, (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. Zwe'u iii. 102, pi. 24, fig. 17. 

 Body black, smooth and shining, marked with minute punctures; 



