PART 111. 



Studies on the Biology of the Kansas Larridae. 



The very general and fragmentary nature of our knowledge 

 concerning the habits of the North American Larridae has in- 

 duced the author to publish the results of his observations on 

 this group of insects. These studies are quite incomplete, since 

 they embrace but a small proportion of the Kansas species, 

 and treat almost solely of the habits of the adults, for while 

 the actions of the latter were in many cases observed in detail, 

 the early stages have been practically neglected. 



The entomological division of the Biological Survey of the 

 University of Kansas made collections in the northwestern 

 portion of the state during the summer of 1910, in the south- 

 western area in 1911. and in the north central part in 1912. 

 Not very much attention was given the Larridte during the 

 first of these surveys; in 1911, however (when the writer de- 

 cided to monograph the Kansas forms), the habits of several 

 species were studied in detail and a large series of the insects 

 secured, while during the ensuing year I was enabled to make 

 numerous additional observations. 



Ever alert and watchful in the hot sunshine, the Larridae are 

 among the swiftest of insects, and readily evade any incautious 

 attempt on the part of the collecter to secure them; on cool, 

 cloudy days they are quite sluggish, and certain species, largely 

 males, may then be taken on various flower heads. In the 

 western portion of the state, species, mostly of the genus 

 Tachytes and Larropsis, appeared to favor the blossoms of 

 snow-on-the-mountain (Euphorbia marginaia) and stinking 

 clover (Cleome serndata), both of which occurred in large 

 patches, while the Russian thistle (Salsola) and a small pros- 

 trate species of Euphorbia, found in sandy situations, proved 

 attractive to others. The latter plant was found to harbor 

 the smaller Larridae, such as those of the genera Tachysphex, 

 Niteliopsis, and Plenocidus. 



Many of the Larridae, particularly of the genus Tachytes, 

 which contain some of our larger forms, produce, when on the 

 wing, a high-pitched buzz, sufficiently characteristic in a few 



(183) 



