518 BOMBYLID.E 



3. ANTHRAX. 



Anthrax Scopoli, Ent. Cam., 358 (1763) ? 



Large, medium-sized, or even small Hies of black or 

 brownish red colour, often bedecked with particolored or 

 pale pubescence. 



Head semicircular, inllated behind but slightly inarched at the middle, as broad 

 as or a little broader than the thorax. Face very short, sometimes conically project- 

 ing but sometimes only gently convex ; mouth-opening large ; ocelli three. 

 Proboscis only a little produced, or withdrawn into the mouth-opening ; sucker-flaps 

 rather broad ; palpi small, thin, and cylindrical, apparently not jointed. Eyes of 

 the male seimrated on the frons, but not quite so widely as in the female, l)oth sexes 

 with an indentation at the middle of the hindmargin. Antennai porrect, short, 

 Avidely separated at the base ; basal joint .short and cylindrical ; second joint cup- 

 shaped ; third joint ranging from the .shape of an elongate cone to that of a 

 flattened onion, with a filiform style ; style not bisected, and with a microscopic 

 bristle but no pencil of hairs at its tip. 



Thorax quadrate with rounded angles, wider behind than in front, and with 

 indistinct priesutural but distinct postalar bristles. Scutellum broad and short, 

 without any marginal bristles ; metanotum completely concealed. 



Abdomen rather flat and oblong, longer than the thorax, with seven segments. 

 Genitalia small and almost hidden, with the male forceps placed asymmetrically in 

 connection with the abdomen ; ovipositor with a circlet of short blunt spines. 



Legs rather long, but not so thin as in JiO)iiJ>i//in.^ ; hind pair lengthened and 

 often bearing conspicuous scaly pubescence, while all the femora and tibite may bear 

 some .shorter more depressed scaly pubescence ; front tibi;e sometimes (piite bare, or 

 sometimes with small spicules ; i^osterior tibia; with an apical circlet of sj^nes ; front 

 tarsi varying in .shai^e and in nature of pubescence ; front claws varying in size ; 

 pulvilli absent or usually very small, but sometimes fully developed. 



Wings in life half open when at rest, very often with variegated markings and 

 spots ; cubital vein with a wide open fork, of which the ujiper branch is strongly 

 S-swung and ending in the costa very much nearer to the radial vein than to its 

 own lower branch, sometimes with a recurrent veinlet from its first bend (showing 

 an inclination towards three submarginal cells) ; radial vein also often showing a 

 recurrent veinlet from its rectangular bend, and with a looj) before its end ; postical 

 fork-cell touching the discal cell for less than half the distance that the third 

 posterior cell does, and sometimes with only a punctiform contact, but the small 

 cross-vein never present ; discal cross-vein u})right and placed at or before the middle 

 of the discal cell ; posterior cells four, all well open ; anal cell open ; a pr^ealar hook 

 occurs close against the base of the wing but is often concealed by pubescence. 



Larvae parasitic on the larvae and pupae of Lejndoptera (A(jrotis, etc.), Hymen- 

 optera, and Orthoptera. 



The flies occur on bare patches and pathways on commons or on sand- 

 hills, and though they readily settle after a peculiar hovering flight they 

 are very quick in tlieir movements and difficult to catch. 



Anthrax is still an enormous and not very homogeneous genus, but 

 Osten Sacken (Biologia Celitrali-Americana Dipt., 1., 112) endeavoured 

 to establish some definite groups to which he gave subgeneric names, in 

 the hope that they would lead to a more accurate subdivision of the 

 genus. Three of those groups are well represented in Europe, and two of 

 them in England, while increased knowledge tends to show that the different 

 groups are parasitic upon the larva? of widely distinct groups (if not orders) 

 of insects. These subgenera may be characterised as follows : — 



Thykidanthrax. — Antero-proximal half of the wings more or less dark, 

 with more or less large subpellucid spots on cross-veins and bifurcations ; 

 abdomen dark with white bands on the third and fourth segments ; the 



