50 SYNOPSIS OF THE DIPTEROUS 
We find an almost identical arrangement of the veins of the 
wings exhibited by this group and by Nemestrina amongst the 
Anthracidee *. 
Olivier, evidently from personal observation of the species which 
he found in Egypt, thus describes their habits, which resemble 
those of Asilus and Dasypogon. “IIs vivent de rapine et font une 
guerre continuelle aux autres insectes, quils attrapent en volant, 
et dont ils retirent tous les sucs au moyen de leur trompe. On les 
voit attaquer les Hyménoptéres les plus fortes et les mieux armés, 
et les emporter entre leurs longues pattes, sans que Vaiguillon de 
ceux-ci puisse les atteindre. Leurs larves nous sont inconnues.” 
To this account I am able to add, from information given to me 
by Mr. MacLeay, that the larvee of M. tricolor (which he observed 
in Cuba) are parasitic upon the larvee of the giant Prionide. 
Wiedemann described all the species known to him under the 
genus Midas; but Latreille separated from them a sub-genus, 
having the proboscis long and porrected, named Cephalocera ; and 
Macquart added a third, Rhopalia, differing only in the alteration 
in the veining of the wings and the thickened mass at the extremity 
of the antenne. If, however, this be admitted, it will become 
necessary to form another for my M. auripennis, which would, I 
consider, be unnatural. Six years ago I described another genus 
from Australia, which I refer to this family, on account of the 
similarity in the veining of its wings, although it is perhaps doubtful 
whether it is not more nearly related to the Nemestrinides. 
Genus MIDAS, Wied. (Mydas, Fabr.) 
Spectres I.—M. heros, Perty. (Del. Anim. Art. Braz. t. 36, f. 11.) Ater, antennis 
ferrugineis, abdominis segmento Imo sulphureo-hirto, alis antice testaceis costa et venis 
fusco-nigris. Long. lin. 26. Expans. alar. lin. 42. Brasilia. 
Species I1.—M. giganteus, Thunberg. (Sw. Trans. 1818, p. 246, Wied. Mon. Mid. 
tab. 52, fig. 1, ¢ @.) Ater, thorace vittis dilutioribus ; abdomine ¢ chalybieo, $ 
vix cerulescente; alis in ¢ cothurnatis vel fuscanis, in © nigris ; margine interno 
apiceque fuscano-flavidis. Long. corp. lin. J5—18 ¢, 20 9. Brasilia. 
Obs. 1.—M. cerulescens, Oliv. Ene. Méth. 8, p. 81, is regarded by 
Wiedemann as identical with the male of this species. Olivier, 
however, says, ‘‘ L’abdomen est d’un bleu trés-brillant,” which will 
scarcely agree with it. ‘The Rev. F. W. Hope possesses a variety 
of the male with the abdomen black, and the front margin of the 
wings pale brown, scarcely darker than the hind margin. 
Species III.—M. dives, Westw. n. sp. Pl. 13, fig. 1. Niger, thorace vittis cinerascentibus, 
abdominis segmento Imo aureo piloso, 2do aureo-sericanti, reliquis lete purpureo- 
ceruleis ; antennis, articulis 2us basalibus exceptis, alisque fulvis, harum basi obscuriori 
margineque postico translucente, pedibus longis 2. Long. corp. lin. 18. Exp. alar. 
unc. 3§. In Mus. D. Hope. 
* Latreille refers to Pangonia, but evidently in mistake for Nemestrina (R. A. 5. 480). 
