664 ASILID^ 



D. trigonus is common and widely distributed over Britain in suitable 

 localities ; it seems to prefer scrubby ground on sandy sea-coasts, but also 

 occurs freely on similar ground inland. I have numerous English records 

 from Penzance to Malvern, while Colonel Yerbury has taken it at 

 Kingussie in Inverness and it is recorded from Irvine Moor and Troon in 

 Ayrshire ; my dates range from May 23 to August 29. Mr K. C. Bradley 

 caught a specimen at Barmouth preying on a Philonicus alhiceps. It is 

 recorded from almost all Europe, but Loew has granted specific rank to 

 some Spanish forms which I can hardly distinguish. 



Synonymy. — There can be no doubt about this species being the Asilus 

 (Lophonotus) cristatus of Walker's Ins. Brit. Dipt., vol. i., p. 50, as it is the only- 

 British species in which the thorax is "bristly to the front," but it cannot be 

 recognised with certainty from Walker's description. 



6. EUTOLMUS. 



Eutolmus Loew, Linn. Ent., iii., 459 (1848). 



Dark grey flies of rather large or medium (not small) size, 

 which have a strong outstanding face-beard on the lower two- 

 thirds of the face. 



Face covered with greyish or yellowish dust ; face-beard strong and outstanding 

 but leaving the upper third of the face bare ; bristles on the lower part of the sides 

 of the frons comj)aratively strong ; postocular festoon usually regular and hardly 

 bent forward. 



Thorax with only short bristles on the fore part even on the middle line and 

 with dorso-central bristles extending from the back part up as far as the suture and 

 sometimes rather beyond but never to the fore part ; the usual bristles are about 

 three (1-3) pra^sutural of which the anterior one may be fairly strong, about three 

 (2-4) supra-alar almost in a row, two or three postalar with sometimes some 

 additional small ones, about four dorso-central postsutural and sometimes (but not 

 always) three or four smaller prassutural ones rather close together but not extending 

 half-way to the front ; metapleural fan not very strong though composed of 

 numerous bristly hairs. Scutellum Avith about six (4-6) upturned marginal bristles ; 

 metanotum with a tuft at each hind coi'ner. 



Abdomen elongate, with ashy grey or greyish yellow (rarely black) reflections ; 

 hindmargins of the segments bearing rather weak though obvious bristles towards 

 the sides of the four or five basal segments. Genitalia of the male rather small, 

 seldom swollen but yet not compressed ; ciaspers always simple, with at most only 

 a small more or less semicircular excision on the inner margin, and not indented 

 about the middle so as to form a forceps ; eighth ventral segment of the male some- 

 times produced at the middle of its hindinargin like a trowel or prong, but often 

 quite simple ; ovipositor moderately long and strongly compressed, bearing at its 

 end a pair of lamellae which are not elongate or stylate but which are always 

 rhomboidal or oval or elliptical and more or less wedged in between the points of the 

 upper piece of the ovipositor (fig. 358). 



Legs black, rather obscured by short close pubescence, and in many species the 

 tibiae (and in some even the femora and tarsi) more or less reddish ; front femora 

 sometimes spinose beneath. 



Wings normal. Squamae with rather long fringes, 



Loew when founding this genus thought that both sexes could be 

 easily distinguished from Dysmachus by the dorso-central bristles as well 

 as the bristles or bristly pubescence on the middle line dying out before 

 the front part of the disc, but he subsequently discovered that there were 

 several species of Dysmachus in which these bristles died out in a similar 



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