160 Descriptions of British Diptera. 



4.' Nemotelus brevirostris. 

 Meig. Zwei. iii. 117. 



The most distinctive mark in this small species is in the form of 

 the rostrum, which is very short and truncated ; the prevailing co- 

 lour of the body shining black, the antennae brownish, and an inter- 

 rupted white line above their base ; thorax with a dilated abbrevi- 

 ated yellowish- white line on both sides ; abdomen with a posterior 

 whitish triangle on the second segment, a semicircular dorsal spot on 

 the fourth, and a transverse white line at the extremity; legs yellow- 

 ish-white, the thighs and hinder tibiae black, with the apex yellow. 

 \\ lines. 



Rare ; inhabits some parts of Middlesex, but no other British lo- 

 calities have hitherto been given for it. 



Genus SARGUS, Fabr. 

 Antennae very short, placed close together at the base, inclining 

 sidewise, the radical joint subovate and truncate, pilose, the second 



cup- shaped and like- 

 wise pilose, the third 

 nearly orbicular, divid- 

 ed into four rings, one 

 of them very indistinct, 

 and having a long nak- 

 ed seta attached to the 

 upper side, (Fig. 1 ;) 

 palpi wanting ; labium large, fleshy and bilobed ; the labrum short, 

 and notched at the apex ; maxillae slender and acute, about the 

 length of the labrum ; eyes somewhat remote in both sexes ; ocelli 

 placed on the forehead, the anterior one generally somewhat re- 

 mote from the others, (Fig. 2;) thorax with a cross suture most dis- 

 tinctly marked at the sides ; abdomen flat, narrow, and much elon- 

 gated in the male, shorter and wider in the female ; scutellum semi- 

 circular, without spines ; halteres rather long, subtrigonate ; winglets 

 wanting ; basal joint of the tarsi as long as all the other joints taken 

 together. 



The flies included in this genus are insects of great beauty, being 

 of very elegant forms, and ornamented with brilliant metallic colours. 

 They are rather inactive in their habits, delighting to repose on the 

 foliage of plants, particularly the glossy leaves of the laurel and 

 other evergreens, during warm and sunny weather. They are sel- 

 dom noticed on flowers, and several of the larger kinds shew no 

 preference to marshy situations, like so many others of the same 

 family, but frequent gardens, shrubberies, skirts of woods, &c. 



