No. 1. — The Parasitic Hymenoptera of the Tertiary of Florissant, 



Colorado. 



By Charles T. Brues. 



The present paper is based upon studies on the parasitic Hymenop- 

 tera contained in the very extensive collection of fossil insects made 

 many years ago by Dr. Samuel H. Scudder at Florissant, Colorado, 

 and now contained in the Museum of Comparative Zoology. In 

 addition, Prof. T. D. A. Cockerell has sent me much material from 

 the same locality obtained by expeditions under his charge during 

 the summers of 1907 and 1908, most of this second series belonging 

 to the American Museum of Natural History. In all I have had 

 the opportunity to examine over 700 well-preserved specimens of 

 insects belonging to this group, among which there are 112 clearly 

 defined species which are described on the following pages. Adding 

 to these the 13 species previously described by Professor Cockerell 

 and the present writer, the total number so far found at Florissant is 

 125. 



The very large number of species of parasitic Hymenoptera repre- 

 sented at Florissant shows it to be by far the richest locality in the 

 world for these insects, as it has already been found to be by Scudder 

 for many other groups. This is shown in the following table which 

 gives a comparison between the several important places where fossil 

 parasitic Hymenoptera have been found. 



Number of Tertiary species of parasitic Hymenoptera found in various 



localities. 



