34 BULLETIN : MUSEUM OF COMPARATIYE ZOOLOGY. 



some certainty, and adequately diagnosed. If the imperfect specimens 

 just mentioned had been all the Hymenoptera found at Florissant, it 

 would have seemed worth while to give them more careful scrutiny, and 

 to describe a number as well as possible. No doubt, by very careful and 

 prolonged comparisons, such portions of the venation as could be deter- 

 mined would be found in many cases to reveal probable or practically 

 certain affinities; but the work would be arduous in the extreme, and 

 would test one's skill to the utmost. As it is, the numerous well-pre- 

 served specimens give us an excellent idea of the fauna, and the deter- 

 mination of the poorer materials may be at least postponed without any 

 serious injury to science. 



In numerous cases, owing to the wings being folded, or one beneath 

 another, the venation looks at first sight abnormal, and will appear to 

 disagree with the descriptions offered. The future student of these in- 

 sects should therefore not conclude too hastily that the descriptions are 

 inaccurate. 



In general terms, it may be said that the Florissant Hymenoptera do 

 not differ greatly from their modern representatives. While some of the 

 extinct genera are apparently more primitive than the dominant genera 

 of the same groups to-day, they are scarcely more so than certain genera 

 which still exist in the modern fauna. Thus, among the Scoliids, we 

 naturally assume that those forms with regular venation, like that of 

 many other wasps, are more primitive — at least in respect to this char- 

 acter — than those with broken or irregular cells. The two fossil genera 

 of this group are therefore less specialized in venation than the common 

 species of to-day, but they are in the same general stage of development 

 as the rare American genus Engycystis, and the Australian Austratij)hia. 

 Thus, if it were possible to restore the Florissant Hymenoptera to their 

 original state, and send them to some entomologist as coming from an out 

 of the way region, he would see in them nothing transcending the pos- 

 sibilities of the modem world. 



It must further be said, that tlie types represented do not suggest 

 tropical or subtropical conditions ; they accord well with the vegetation 

 in indicating a climate like that of the austral zones of the temperate re- 

 gion. The bees are principally of genera found flying in Colorado to-day, 

 and there is no indication of the types especially characteristic of Mexico. 

 Both among the bees and the wasps, the element which we regard as of 

 neotropical origin is conspicuously absent. It is only just to remark, with 

 regard to the bees especially, that the generic identity assumed from the 

 parts preserved might in some cases be belied, could we examine the 



