5. DYSMACHUS 657 



terminal joint ; the ventral plate liears some moderate black bristly pubes- 

 cence near its end but thinner shorter and partly pale pubescence near its 

 base ; the end joint with very short brownish orange pubescence. 



Logs with the black pubescence beneath the front femora more crowded 

 and most bristly close to the base. 



Wings with the basal part less milky white. 



Length about 16 mm. 



This species is easily distinguished from any other European species of 

 the Asilinm by the hairy pubescence and peculiarly colored wings, unless 

 the var. hclveticus Mik should prove to be distinct ; that variety has the 

 abdomen steel blue and the bristles on the hind tibiae mainly orange, and 

 in the only specimen I have seen the prtesutural bristles were yellow and 

 the thoracic middle stripe was not split ; English specimens may vary a 

 little in the exact number of bristles on the femora and tibiae but not 

 much otherwise, though in a small female the face-beard and some of 

 the antero-dorsal bristles about the middle of the hind femora are mainly 

 black; continental specimens show the black pubescence near the base 

 of the underside of the front femora more like a clump of bristles, and 

 also always seem to show longer pale pubescence behind the hind femora 

 especially towards the base, while the middle femora seem to have longer 

 and stronger bristles on the underside. 



P. gcrmanicus appears to be dying out in England, as recent captures 

 are very few, though it used to occur in old collections. I found eight 

 specimens on the sand-hills at Barmouth on June 10 and 11, 1887, 

 and Colonel Yerbury took five specimens near there on June 27, 1902 — 

 I believe the exact 1887 locality was built over in 1902 — and he has 

 also taken a few specimens since at Porthcawl in Glamorgan, and Mr 

 P. H. Grimshaw has recorded it from Irvine Moor in Ayrshire on the 

 authority of Mr A. Adie Dalglish. My specimens were immature, but 

 Colonel Yerbury's specimens (taken about sixteen days later) were quite 

 mature, while on July 20, 1888, I was unable to find a single specimen 

 (F. alhicGjJS having taken its place); I am therefore of opinion that it 

 occurs for only a short period during the latter half of June and the 

 beginning of July ; one of Colonel Yerbury's specimens was preying upon 

 a red Ayhodius. Curtis recorded it from Devonshire. 



5. DYSMACHUS. 



Dysmachus Loew, Dipt. Sud-Afrik., 143 (1860). 



Grey rather bristly flies of medium or rather small size. 



Head sometimes (as in our British species) unusually pubescent. Face with a 

 rounded produced face-knob which does not extend to the upper third of the face, and 

 consequently the face-beard (which is composed of long and abundant bristles and 

 hairs) leaves about the upper third of the face bare. Festoon composed of irregular 

 long bristles or bristly hairs, of which at least some are rather curved forward. 

 Antennae normal, the third joint being of the usual elongate oval form (tig. 356) though 

 sometimes only very narrowly ovate but never so linear as in J'rotophanes (fig. 355). 



Thorax with dorso-central bristles (or dense bristly pubescence on the middle 

 line) extended to the front part, or at least the dorso-central bristles continued 

 conspicuously much in advance of the suture, while sometimes the long bristly 

 pubescence on the middle line is extended conspicuously and mane-like right up to 

 the front, and in such cases the dorso-central bristles are almost merged into this 

 bristly pubescence. Bristles (macrochseta^) consisting of three or more pra^sutural 

 (including a more or less strong anterior one), about six (rarely only two) supra-alar 



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