ANTHEAX. 113 



Anthrax, Nos. 8-10) &c. A species of tropical aspect, A. cyanoptera, Wiedem., belongs 

 in the same relationship of species with a conical face and Exopr osopa-like front legs 

 and tarsi ; its proboscis is much more elongated than that of the other species, its 

 colours metallic. 



All the above-mentioned groups have smooth front tibiae. A smaller number of 

 species have the front tibiae beset with spinules. Among these, Anthrax cuniculus, 

 A. consul, and A.jpalliata (Nos. 15-17), besides some common characters in the coloration 

 of the body and wings, have the front tarsi with very distinct joints, the underside beset 

 with minute, dense bristlets and hairs, while the pubescence on the upperside is incon- 

 spicuous, and comparatively large ungues; in the structure of the third joint of their 

 antennae (more or less elongate-conical gradually merging into a style) and their conical 

 face they resemble the group of species sub Nos. 1-13. Their wings are brown on 

 the antero-proximal half, the brown encroaching but little on the axillary cell, and not 

 showing any darker or paler spots, except the usual subhyaline spot before the discal 

 cell. The A. ephebus (No. 14) seems to be closely allied, but has the cross-veins infus- 

 cated in the brown as well as in the hyaline portion. 



Anthrax castanea (No. 18) has the same conically projecting face and the conical third 

 joint of the antennae; the structure of the front tarsi is likewise the same as in the 

 preceding group, but the coloration of the wings is different (brown cross-bands, 

 alternating with hyaline ones). 



Finally, A. rex (No. 19) and A. parvicornis, Loew, have nearly the same structure of 

 the front legs and coloration of the body and wings as Nos. 15-17 ; but in these species 

 the face is rounded and not conically projecting, the third joint of the antennae is almost 

 onion-shaped and with an abruptly beginning filiform style, and the proboscis projects 

 far beyond the oral margin. 



Thus, among a comparatively small number of species, we find structural differences 

 which, in other families than the present, would justify a generic separation. It is 

 possible, however, that, with the increase in the number of species known and studied, 

 intermediate forms may occur. The best course to pursue, in order to avoid uncertainties, 

 as well as a too great multiplication of genera, will be to go on with the formation and 

 definition of groups, but to treat such groups merely as subgenera ; intermediate forms 

 of uncertain location thus would be left in the genus Anthrax in the wider sense. The 

 subgenera, admitting of a closer definition, may receive names formed of combinations 

 of the word Anthrax, like Lepidanthrax, Hyalanthrax, Thyridanthrax, Pcecilanthrax, 

 Chrysanthrax, &c. The advantages of such a grouping within a large genus for 

 purposes of describing and identifying species are evident. The genus Trypeta has 

 been treated in the same fashion ; its numerous subdivisions are mere subgenera, and the 

 genus Trypeta, sensu latiori, is still maintained ; but these subdivisions have greatly 

 simplified descriptions, and rendered determinations more easy. 



biol. cente.-ambk., Dipt., December 1886. q 



