Jan., 1906.] How to Collect Stylopidae. 443 



HOW TO COLLECT STYLOPIDAE.* 



Charles Durv. 



It is well known to entomologists that many genera of wasps, 

 bees and insects of other orders, are at times affected with par- 

 asites which live in their abdominal cavities. In the genera 

 Xenos and Stylops, the adult female is larvaform and never 

 leaves the body of the host, but the male when readv to pupate 

 projects the end of the pupa case outwards, between the seg- 

 ments, where it can easily be seen protruding. By examining 

 wasps and bees when they frequent flowers, it can readily be 

 observed as to whether or not they are parasitized. The female 

 Xenos can be distinguished from the male by the broad flat 

 projecting head. The male pupa case is rounder and separates 

 the segments to a greater extent. When a wasp is found with 

 male pupa, it may be secured and brought home alive. Confine 

 it in a jelly tumbler with a cheese cloth cover over the top; in 

 the bottom of the glass there should be placed a round bit of 

 blotting paper and a piece of screen wire, raised up from the 

 bottom. This is necessary because the instant the Xenos hatches 

 the wasp rushes after it, in an endeavor to catch, kill and bite it 

 to pieces, an example of an interesting instinct. The move- 

 ments of the Xenos are so rapid, that the wasp can not catch it 

 until it falls exhausted in the bottom of the glass. Bv having 

 the false bottom of wire, the Xenos falls through, the wasp not 

 being able to follow, and the specimen can thus be secured. 

 The wasp while confined in the glass must be fed. This may be 

 done with jelly and water, putting it on the cheese cloth cover 

 in one small spot, with a camel's hair brush. Many fine spec- 

 imens have been hatched by the writer in this way, from five 

 genera of wasps, several of which are new host wasps, and the 

 facts and species obtained are entirely new to science. There 

 are yet some interesting problems in the life history of these 

 curious insects that are unknown. In looking through some of 

 the largest and finest collections of insects recently at Wash- 

 ington and New York, only a few poor specimens in this family 

 were found while in some otherwise valuable collections they are 

 not even represented. In view of a monograph of these insects 

 in course of preparation by W. D. Pierce, the publication of 

 which will occur soon, material from all parts of the country is 

 very much desired. 



* Presented at the Ohio St. Acad, of Sci., Cincinnati meeting, Dec. 1, 1905. 



