A Fossil Tsetse-fly in Colorado

Abstract

AMONG the interesting materials obtained this year in the Miocene shales of Florissant, Colorado, is a large “biting” fly, with a remarkably long and strong proboscis, very well preserved. A very superficial examination was sufficient to show that it was no ordinary Tabanid or Muscid, and it at once occurred to me that it was a tsetse-fly. Having no specimen of the latter at hand, I turned to the admirable coloured figures in the second report of the Wellcome Laboratories at Khartoum, and, as was expected, it matched so nearly that it might well go in Glossina. There is a slight difference in the venation which may or may not be of generic value, but if the insect is not a Glossina it is at least closely allied. Curiously, it is not new, for it appears to be the species described by Scudder in 1892 as Paloestrus oligocenus, a supposed new genus of stridæ. The new specimen, practically complete, and with the mouth-parts, shows that it has nothing to do with stridæ, and anyone who will refer to Scudder's figure will see how closely the venation resembles that of Glossina.