Descriptions of British Diptera. 161 



They probably derive their nourishment from the saccharine juices 

 which frequently exude from the leaves of plants. We are 

 still imperfectly acquainted with their larvae. One described by 

 Reaumur was found to live in cow-dung. It was of an oblong fi- 

 gure, narrowing to a point anteriorly, and furnished with two hooks 

 at the head, which is of a scaly texture. Its metamorphosis took 

 place within the skin of the larva, and the fly made its exit by push- 

 ing outwards the portion that covered the head and first segment. * 



1. Sargus cuprarius, (s.) 



Musca cupraria, Linn. Fair Nemotelus cuprarius, De Geer, vi. 200, tab. 



12, fig. 4. — Sargus cuprarius, Fabr. Syst. Ant. 

 Forehead bluish-black, shining and pubescent, narrow in the 

 males, somewhat wider in the females ; antennae brown, with a small 

 white spot over the base of each ; eyes brassy green during life, with 

 a horizontal purple band a little above the middle, the superior space 

 more or less inclining to that colour, particularly behind ; thorax 

 shining golden-green, pubescent, the sides blue-black ; halteres pale 

 yellow, or whitish ; wings vitreous at the base, more or less clouded 

 with brown in the middle, especially from the anterior margin across 

 the discoidal cell ; abdomen cupreous, shining and pubescent, the 

 hinder parts more or less glossed with violet, the whole being of the 

 latter colour in the female except at the base ; the under side shin- 

 ing black inclining to blue ; legs black, the tip of the thigh, base 

 of the tibiae, and some of the joints of the tarsi inclining to reddish- 

 yellow. 4-5 lines. 



This beautiful insect is found from May till August, and seems 

 to be not uncommon in most parts of the country. It frequents gar- 

 dens, shrubberies, and sheltered lanes, and is not observed much on 

 the wing, but reposing on the foliage, as if enjoying the sunshine. 

 It has been noticed in many parts of Scotland, and it is sometimes 

 rather plentiful in the Botanic Garden of Edinburgh, and other 

 places near the Scottish metropolis. The female is always much 

 more plentiful than the male. " I found this splendid insect 

 in abundance on the borders of a wood near Dover, on the 14th of 

 July, and took a female in Scotland the same month." — Curtis, B. E. 

 vii. fol. 305. " Near London," Stephens. " Dunkeld and Dum- 



* Reaumur, Memoires pour VHistoire des Insectes, iv. 348 — It is difficult to 

 determine from his rude figure, (pi. 22, fig. 7-8,) what species of Sargus origi- 

 nated from this larva ; it cannot be S. cuprarius, as De Geer and Latreille sup- 

 pose, (Regne Animal, v. p. 487,) for the belly and legs are described as being 

 pale yellow. Meigen conjectures that it is the species which has since been 

 named S. Reavmuri. 



NO. II. L 



