DIAPHORUS. 215 



Genus XII. DIAPHORUS. 



DlAPHOKTJS, Mg. zw. iv. 32 (1824); Mq. ; Ztt. Dolichopus p., Fin. ; 



Mg. 

 Antenna articulo tertio patell&formi, arista dorsali. Oculi maris fronte 



contigui. Hypostoma latum. Vena prcebrachialis simplex, transversa 



ab alee margine distans. Hypopyyium maris subimmersum, subtus ap- 



pendicibus binis anyustis deflexis. 



Antennae short, with the first joint naked, the third joint broader than 

 long, rounded : the arista placed on its upper edge, long, slender, finely 

 pubescent. Eyes finely pubescent, meeting on the front in the male, 

 distant in the female. The face broad in both sexes, and rather short, 

 especially in the male, the antennae being more distant from the vertex 

 than usual. Occiput with a whitish beard behind the lower orbit. 

 Proboscis very short, projecting a little forwards. Wings like those 

 of Argyra, being broad about the anal angle, and the subcostal vein 

 longer than in other genera ; the praebrachial vein simple as in most, 

 not forked as in Psilopus, and the subapical portion of it straight and 

 parallel with the cubital, the discal transverse vein distant by much 

 more than its own length from the hind margin. Fringe of the alulae 

 black. Abdomen conical in the female, in the male rather compressed 

 behind, with the sixth segment exserted, the small hypopygium partly 

 imbedded under the lip of it, armed behind with some spines, and 

 beneath with two slender, deflected, pubescent appendages, besides the 

 stouter forceps which is for the most part hidden in the ventral cavity. 

 The structure differing little from Argyra, and not much from Chry- 

 sotus. The hind margins of the abdominal segments are a little ciliated 

 at the sides. Legs rather long and slender, the spines of the tibiae 

 few and slender, the fore pair with scarcely any, the femora much 

 more hairy in the male, the hind metatarsus unarmed, about as long as 

 the following joint. The males are at once known from every other 

 genus by the eyes meeting on the front ; the females may be more 

 easily confounded with other genera, but the form of the third joint of 

 the antennae and the insertion of the arista in connection with the length 

 of the subcostal vein will help to separate them. The colour is 

 usually dark. 



1. oculatus, Fin. dol. 28. 22(1823); Ztt.Jlavocinctus, Mq. ; 

 Mg. Fcem. tuberculatus, Mg. jEneus, capite cinerascente, antennis pe- 

 dibusque niyris, alls subfuscis, halteribus pallidis, femorum anterior urn 

 apice lato tibiisque omnibus flavis ; Mas. abdomine in basi fascia pallida 

 subpellucida. Long. 2 ; alar. 4 lin. 



Brassy. Head with a greyish covering. Mouth and antennae black. 

 Wings slightly brown. Halteres pale. Legs black ; anterior femora 

 yellow towards the tips j tibia yellow. Male. Hypostoma broad, very- 

 short, whitish. Eyes bluish-violet, with brassy borders. Palpi small, 

 ferruginous. Abdomen with a yellow semipellucid band on the second 



