No. 2. — Fossil Hymenoptera from Florissatit, Colorado. By T. D. A. COCKERELL The Tertiary shales of Florissant, Colorado, have been made famous through the writings of Lesquereux and Scuddei-, wherein are described hundreds of species of plants and insects preserved in hue volcanic ash and sand. The vast multitudes of individuals and species, and the won-derful state of their preservation, render the locality perhaps the richest of its kind in the world, and afford us as good an opportunity as could be loolved for to reconstruct the fauna and flora of a remote age. Just what age this is, is a matter in dispute ; but for various reasons, which I give in a paper to be issued in the University of Colorado Studies, I think it is almost surely Miocene. Unfortunately, Mr. Scudder has not been able to finish the investi-gation of the materials he secured at Florissant. In his work on Tertiary Insects (1890) he indicated briefly the great wealth of undescribed species. Since then he has published some miscellaneous species (Bull. 93, U. S. Geol. Surv., 1892), the Rhynchophorous Coleoptera (Monog. U. S. Geol. Surv., 1893, 21), the Adephagous and Clavicorn Coleoptera (Monog. U. S. Geol. Surv., 1900, 40), and the Tipulidae (Proc. Amer. Philos. Soc, 1894, 32). The great work accomplished by Mr. Scudder can in some measure be understood by one who has learned the difiiculties of this kind of investigation ; the eye-strain involved in determining minute and often nearly obliterated features, and the wide knowledge and good judgment necessary in order to classify specimens which only exhibit part of the characters commonly used as diagnostic. It is not to be expected that another such master of palaeoentomology will appear to take up the work ; but the valuable materials must not be neglected, and we may hope that with the aid of several workers they will all be made known. The present contribution deals with the bees and wasps, and one species of Stephanidae, kindly entrusted to me by the Museum of Comparative Zoology. In addition to the species described, I have examined more imperfect specimens of perhaps as many otliers ; but it has seemed best to publish only those which could be classified with VOL. L. — No. 2 3
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