No. 2. — Fossil Hymenoptera from Florissant, Colorado, 

 By T. D. A. Cockerell 



The Tertiary shales of Florissant, Colorado, have been made famous 

 through the writings of Lesquereux and Scudder, wherein are described 

 hundreds of species of plants and insects preserved in fine 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 looked 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 difficulties 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 others ; but it 

 has seemed best to publish only those which could be classified with 

 vol. l. — No. 2 3 



