642 ASILID^ 



between the suture and tlie hindmargin but can seldom be confounded with the 

 strong bristles (macrochsetse), and in some cases {Dysmachus and Lophonotus) the 

 small bristles on the middle line may be as long as the macrochsetae even to the 

 fi'ont part of the disc. Bristles (macrochsetas) following very similar arrangements 

 in all the species though varying in numbers ; prsesutural usually consisting of 

 two strong ones, though sometimes {Ujnt7iptus) there may be only one strong one, 

 while in other cases (Pampaneims, Asilus, Dysmachus, etc.), there may be five or 

 six, and often when there are only two strong ones there may be one or more 

 weaker ones in advance (nearer the foremargin of the thorax) ; supra-alar (as 

 distinguished from the " postalar " which are placed on the postalar callus) usually 

 about three distinctly supra-alar, but varying from two to five or six and sometimes 

 these bristles are placed so far from the wing-base as to appear intra-alar (Asilus, 

 etc.), or the supra-alar bristles may form a sort of row which may extend almost 

 intra-alarly {Pamponerus) ; postalar usually about two strong ones but varying from 

 one to six, with some additional weaker bristles usually present ; dorso-central in 

 two well defined rows but varying in numbers, extent, and strength, as they often 

 die down towards the hindmargin so much that they may be lost in the ordinary 

 pubescence, while often they may not extend forwards in front of the suture {Asilus) 

 or they may extend as far as the front of the thorax though then they are hardly dis- 

 tinguishable from the long dense bristly pubescence on the middle line. Pleurae with 

 only moderate and usually inconspicuous pubescence except for the metapleural 

 and hypopleural fans, both of Avhich are always obvious, though the metapleural 

 fan may be composed of long hairs of any degree of strength from soft hairs to stiff 

 bristles, while the hypopleural fan usually has its two or three uppermost hairs 

 or bristles even stronger than those on the metapleuriJe but the subsequent hairs 

 or bristles weaker ; some soft fine pubescence always exists on the prothorax and 

 on the space between that and the front coxae, while at least traces of fine 

 pubescence occur on the upper and hind parts of the mesopleur^, on the ptero- 

 pleuraj (generally rather more bristly), and on the upper part of the sternopleurce, 

 besides some fine hairs about the metapleural and hypopleural fans. Scutellum 

 usually with fine pubescence on the disc, but sometimes this pubescence is repre- 

 sented by tiny bristles (Asilus), and always with some long upturned marginal 

 hairs or bristles. The colour of the bristles (both small and large) affords some 

 valuable specific distinctions but yet is liable to variation within certain limits, 

 and must therefore be accepted with doubt when applied to individual bristles. 



The markings of the thorax are generally persistent in each species, but not so 

 invariably as to provide good specific distinctions in all cases, yet they are so charac- 

 teristic in some species that they give important means of identification. The most 

 conspicuous marking is as a rule the middle steipe, which begins rather widely 

 quite anteriorly but narrows posteriorly in most species and as a rule does not quite 

 extend to the hindmargin or is carried on only as a narrowing stripe or spot ; this 

 middle stripe is usually split (at least in front) by a pale line which is called the 

 MIDDLE LINE. Next to the middle stripe come the (usually distinct) side stripes, 

 which however are sometimes entirely absent ; when present and complete each 

 stripe is composed of three parts, of which the front part is praesutural but does 

 not extend to the front of the disc, and the middle part is postsutural being separated 

 from the front part by a sloping pale line which follows the suture, while the third 

 part is an awl-shaped spot rather close to the middle stripe and i^ointing towards 

 though not reaching the hindmargin. There is also usually a dark humePwVL stkipe 

 on each side Avhich slopes from the humeral region and may curve round towards 

 the front end of the side-stripe or may extend clown alongside the middle stripe. 

 The thoracic markings will be found to vary in colour and shape according to the 

 light and the direction from which they are viewed, and consequently it is necessary 

 when describing these markings to indicate the point of view ; the usual point of 

 view accepted for producing the most sharply defined markings is obtained by 

 looking down on the specimen held perpendicularly with its head farthest away 

 and with the light shining from in front. 



Abdomen rather long and narrow, without any conspicuous lateral tufts of 

 pubescence ; usually with but little pubescence and consequently very dift'erent 

 from the humble bee-like Laphrince, but with exceptions ; the actual hindmargins 

 of the segments (especially the second segment) usually have a more or less narrow 

 bare hem ; eighth segment often dorsally or entirely concealed in the male, and 

 often providing valuable distinctive characters in the form of its ventral hind- 



