2 1 '2 Descriptions of British Diptera. 



the wing like the bombylii. Very few species are known ; and al- 

 though that described below has been admitted into our indigenous 

 lists, the fact of its being a native requires confirmation. 



Ploas virescens. 



Meigen, ii. 231. pi. 19, fig. 6 — Ploas hirticornis, Latr. Gen. Crust, iv. 312, 

 pi. 15, fig. 7. — Bomb. Maurus, Mikan, pi. 4, fig- 13.— Conophorus Maurus, 

 Meigen, Klassif. pi. 10, fig. 17. 



Surface of the body obscure green, nearly black, invested with 

 greyish hairs ; forehead whitish in the male, with fulvous hairs in 

 the female ; first and second joints of the antennae greyish-brown, 

 with very long black hairs ; third joint black. Hairs on the thorax 

 ferruginous ; sides of the breast whitish ; scutellum small, shining 

 black and naked : abdomen rather broad, blackish green, clothed 

 with ferruginous hairs ; that of the male with alternate tufts of 

 white and black hairs on the sides : wings brownish at the base, the 

 transverse nervures likewise bordered with brown : tibiae yellowish, 

 the thighs and tarsi somewhat obscure. 3 — 4 lines. 



The principal station of this insect seems tobe in the South of Eu- 

 rope; but it has been found as far north as Paris ; and specimens 

 in the British Museum are said to have occurred in this country. 



Family— CONOPID.E. 



Antennas three-jointed, angular at the base, the third joint with 

 a terminal style ; proboscis long and slender, geniculated at the 

 base ; ocelli wanting ; thorax without a cross suture ; abdomen 

 curved inwards at the extremity, and consisting of six segments in 

 the female, and seven in the male. 



As constituted by Dr Leach, and adopted by several other authors, 

 the family Conopidas was made to include the genera arranged be- 

 low as a distinct group under the name of Myopidae. This sepa- 

 ration was first made by Macquart, and is rendered necessary by 

 the important difference of character which they present, as will be 

 seen by comparing the respective descriptions. As it now stands, 

 the present family is restricted to the old genus Conops of Lin- 

 naeus. 



Genus CONOPS, Linn. 

 Antennae rather longer than the head, inserted on a frontal protu- 

 berance, placed close together at the base and diverging at the apex, 

 the radical joint short, slender, and cylindrical, forming an angle with 

 the second, which is horizontal and elongated, increasing in thickness 

 from the base, and forming with the third a compressed club, ending 



