110 [May, 



present s[)ecies ; Bigot's II. Dehirouzci. described in iSoS from three 

 specimens also taken in a cave (Grotte de la moiitagnc Noire, Depart- 

 ment du Tarn) is as he himself acknowledged in 18SG identical with 

 Meigen's atricornis. 8chiner's description of Thelida occuhtta must 

 refer to the present species, while his H. atricornis is probably a true 

 Tepliroclilamys^ as Girschner has already pointed out. Rondani's 

 Thelida diversa (1867) is almost certainly another synonym. 



2. — H. ROTUNDicoRNis, Zettorstodt. 



t? . Frons at the vertex only about three times 

 as wide as the posterior ocelli are apart, and about one- 

 thirl narrower just above the antennre ; the face is not 

 narrower than the frons, and gradually widens out until 

 at the lower corners of the eyes it is about one-half the 

 width of the head ; frons all dull red, but with the 

 ocellar triangle brownish-black, there are two pairs of 

 fronto-orbital bristles, the front pair situated about half 

 way down the frons ; the face is yellowish, but whitish- 

 grey bri ween the antennae, in the antennal grooves, and 

 on the jowls ; the back of the head is more the colour *"■«■ '^■-"- rotun.Uconiis, <J. 

 of llie pleurae. 



Thorax and scutellum dark brown, as the usual four dark stripes on the thorax 

 are very broad, and occupy almost the entire disc, only leaving a narrow central 

 line and two other very indistinct side lines just outside the dorsal rows of bristles, 

 of a lighter colour ; the pleur.ie and metanotum are slaty-grey, but that part of the 

 pleura round the root of tlie wing, including the top of the stornoplcura, is tinged 

 with brown. There are five pairs of the outer dorsal rows of bristles strongly de- 

 veloped, one pair being in front of the thoracic suture. 



Legs all pale except the front femora, which are obscured about the middle, 

 and all the tarsi which are darkened about their tips ; the prteapical bristles on the 

 tibia3 are very small, and the apical spur of the middle tibia is very little longer 

 than the tibia is wide, while that of the hind tibia is hardly visible. 



? . Very different to the male, because of its wide frons, jiointed and not 

 narrow or particularly bristly abdomen, and its general lighter colour, but very like 

 the female of atricornis. The frons is quite one-third the width of the head, and 

 is reddish about the centre and front, but the ocellar triangle and side lines are grey; 

 the face is the same width as tlio frons, not \\a,rvo-wev ViS \r\ atricornis ; antenna? 

 large and black. 



Thorax much lighter gi-ey than in the male, but a dai-ker grey than the plcurte 

 and with four faint dark stripes. 



H. rotmidicornis is apparently the commonest British species of 

 the genus ; I have seen numerous males from Lairg, Inveran, and 

 Bannoch, in Scotland (June, July), from Slapton in S. Devon (Sep- 

 tember), Barmouth in Wales (June), Warrengore in Sussex (April), 

 Glanvilles Wootton in Dorsetshire (February), according to a speci- 



