THE SAWFLIES OF BOULDER COUNTY, COLORADO 93 



They may be bred by using means similar to those described for all 

 leaf-feeding larvae. Mr. Cushman 1 has recently stated that he has 

 secured better results by keeping the food supply in damp sand, 

 covering the same with a lantern chimney, the top of which is screened. 

 In studying the immature stages it is desirable, if possible, to ascertain 

 the exact length of the pupal period. The larvae spin a cocoon in 

 which they contract themselves, and remain in a prepupal condition 

 for a long time. They then change to a pupal stage which is, as a 

 rule, short, after which they emerge as adults. 



Certain groups are, as yet, not known from the county. More 

 collection will, no doubt, bring representatives of the family Cim- 

 bicidae, subfamily Arginae, subfamily Cladiinae, subfamily Empriinae, 

 family Cephidae and family Megalodontidae, besides many additional 

 species in groups already represented in the fauna. Of the latter one 

 would expect many more Nematinae (including Hoplocampa) and 

 Tenthredininae. 



The plan of the following paper is to give a list of all the species 

 known to occur in the county, with characters to separate all the 

 genera and higher groups, as well as the species, from all other groups 

 and species. In preparing this paper published and manuscript notes 

 have been used, and it is believed that, up to the time of writing, the 

 characters given will separate the genera or species from every other 

 genus and species described. It is necessary, however, that more 

 elaborate descriptions should be consulted for certain groups. A brief 

 bibliography of articles referring to Boulder County Chalastogastra, 

 or papers necessary in a study of the fauna, is added. Although this 

 is not complete it will serve as a beginning. 



Order HYMENOPTERA, Suborder Chalastogastra 



The suborder Chalastogastra forms a very distinct group within the order Hymenop- 

 tera. It includes the insects commonly called sawflies (or leaf-wasps) and horntails 

 (or wood- wasps). The insects belonging to this suborder may be distinguished from all 

 other Hymenoptera (suborder Clistogastra) by the following characters: 



Adults. — (1) First abdominal segment not transferred to the thorax and forming a 

 part of it, i.e., the abdomen is consolidated with the metathorax by its entire width, and 

 the second abdominal segment connected with the first for its entire width. (In the 



1 Proc. EnL Soc. Wash., Vol. XIII, p. no, 1911. 



