2. ASILUS (sENSU STRICTISSIMO) 645 



Abdomen long and curved, conspicuously black or partly orange ; eighth segment 

 concealed dorsally, but short and simple ventrally. Pubescence mainly composed of 

 minute liristlcs, but with longer tufts at the sides of the basal segments (occurring 

 on the second segment a])OUt the middle of the sideraargins) ; no hindmarginal 

 bristles, lielly with minute bristles, besides the pendent long hairs on the basal 

 segments. Genitalia rather small ; claspers moderately dentate after the middle on 

 the inner side ; ovipositor conical and pointed, not at all compressed laterally nor 

 with any terminal circlet of spines. 



Legs strong, mainly orange ; tarsal joints neither unusually long nor short. 

 Pubescence slight, and the usual strong bristles rather numerous but comparatively 

 short. 



Wings with a brownish orange tint, and with conspicuous brownish apical and 

 hindmarginal spots or dashes ; cubital fork with a very slightly bell-shaped opening ; 

 third veinlet from the discal cell curved round to the upper branch of the postical 

 vein (fig. 339). Squaniai (alar) with a single fringe on the ujjper part of the margin 

 but a dense outspread pubescence on the lower part. 



This genus is very distinct from any other European one, but such 

 a vast number of species have been described under the term Asilvs that 

 it is not easy at present to define its limits. It needs no comparison with 

 any other Palsearctic genus. 



Asilus in its most limited restriction includes in Europe only two 

 well known species, of which one (A. barbarus) is confined to the Medi- 

 terranean district, but a considerable number of species are recorded 

 (perhaps not truly congeneric) from North America and South Asia. 



Siftionymy. — Linne's conception for this genus in his Systema Naturae, Ed. x., 

 605 (1758) included twelve species of which six are recognised as well-knoAvn species 

 of the yls^7^V/fc, and three others are believed to be true Asilidoe ; his first species 

 A. matirus has not been recognised, but as he compared it with A. crahroniformis 

 the latter may well be considered the type of the genus. 



1. A. crabroniformis Linne, Abdomen basally black but orange after 

 the third segment. 



A large handsome fly with a light brown thorax, black 

 basal half and orange apical half to the abdomen, and macu- 

 lated hindmargin to the wings. 



S . Head nearly as broad as the thorax and more than twice as broad as long ; 

 frons near the antennae when seen from above not sunk between the eyes. 

 Face broad (one-third the width of the head) and very little wider at the 

 mouth than at the antennae, but the frons slightly widening out just above the 

 antennae though very slightly contracting again towards the vertex ; face and 

 frons covered with golden tomentum ; lower half of the face down to the 

 upper mouth-edge produced into a rounded projection which can hardly be 

 called a facial knob, and on this projection with a long strong drooping 

 face-beard composed of bristle-like yellow or deep orange hairs, and these 

 hairs extend down the sides of the mouth for more than half-way to the lower 

 mouth-angle, but the upper half of the face and the lateral thirds are bare ; 

 after the face-beard ceases there is a bare rather blackish interval before the 

 commencement of the long dense pale yellow pubescence which occurs on 

 the back of the head and round under the chin ; this pale yellow pubescence 

 is long for about one-third the way up the back of the head, but after that 

 becomes shorter (though still long) and extends as almost a single-line bristly 

 festoon quite up to the vertex, but is all the way well set back from the eyes 

 by the intervening broad orange eyemargin, though on the eyemargin itself 

 some shortish inconspicuous yellow pubescence exists close to the bristly 

 fringe ; near the vertex this festoon widens out into three or four bristles 

 wide and the bristles on the front part usually curve a little forwards at their 



