ARGYRA. 207 



Genus X. ARGYRA. 



Argyra, Mq. d. i. 456 (1834) ; Mg. vii. Porphyrops p., Mg. ; Ct. ; 

 Hal. DolicJiopus p., Fb. s. a. ; Fin. ; Ztt. Musca p., Fb. ; Dnvn. 



AntenncB ariicnlo secnndo oblique prodticto supra basim tertii, tertio 



apice attenuato; arista ante apicem aut apicali. Oculi f route distantes. 



Ala latce, vena siibcostall costam dimidia^n accedente. Hypopytjium 



maris immersum, lamellis geminis dejlexis. 



Antenna with the first joint usually pubescent above, as in DoUcho- 

 piis (except species 6) ; second joint obliquely lenythened over the base of 

 the third, which tapers to a point and bears the arista before the tip or 

 close to it ; the third joint is usually elongated, and the arista shorter, 

 in the male, liyes pubescent, distant on the front. Face narrow in 

 the male, broad in the female ; lower occiput clothed with a soft beard 

 of the same colour as the face. Proboscis very small in male, promi- 

 nent in female, obtuse. Scutellum with two long bristles at each side, 

 the disc flat and naked (except species 2). Prosternum a little hairy 

 at each side, without spines (except species 2). Winys broad, not 

 narrower at the anal angle, the subcostal vein, longer than usual, endiny 

 nearly opposite the tip of the discal areolet (except species 7) ; cbscal 

 transverse vein distant by nearly twice its own length from the hind 

 margin. Alulae with a long fringe and usually edged with black 

 (except species 1). Abdomen of five segments, conical, depressed in 

 female ; in male of six segments, less attenuated behind, and rounded 

 at the tip, where the short subglobose hypopygium is imbedded, Avhich 

 bears below a pair of small deflected lamellfe connected at the base, 

 and ends with a short forceps closely applied to the ventral cavity. In 

 species 7 alone the abdomen of the male is decidedly compressed. 

 The coxae all with black bristles or hairs ; posterior femora with one 

 or two spines near the tip ; fore tibiae usually with very few spines, in 

 species 2 more numerous (as in the posterior pairs) and in a double 

 row ; hind metatarsus usually rather shorter than the following joint, 

 equal to it in species 3, longer in species 1 ; the other metatarsi elon- 

 gated, the fore one often longer than all the other joints together in the 

 males. — Most of the species have a silvery gloss, most decided on the 

 abdomen of the male ] the abdomen besides is usually pale at the base 

 beneath, and at the sides of the second and some of the following- 

 segments. — The last group of the genus Rhaphium might be better 

 combined with the present genus, on account of the structure of the 

 antennae in particidar, to which there is an approach apparent in 

 A. vestita. 



The British species may be arranged as follows : — 



a. First joint of the antennae pubescent above. 

 b. Scutellum pubescent. Species 2. 

 b b. Scutellum naked on the disc. 



