THE EFFECTS OF PARASITIC AND OTHER KINDS 

 OF CASTRATION IN INSECTS^ 



WILLIAM MORTON WHEELER 



With Eight Figures 



I. THE EFFECTS OF STYLOPIZATION IN WASPS AND BEES 



The perusal several years ago of a very interesting paper by 

 Perez ('86) on bees of the genus Andrena infested with Stylops 

 led me to undertake a similar study of our North American wasps 

 of the genus Polistes parasitized by Xenos. I began to collect 

 stylopized P. variatus during the autumns of 1898 and 1899, while 

 I was living in Chicago, but the wasps proved to be too scarce to 

 serve my purpose. During the summer of 1900, however, while 

 I was spending my vacation at Colebrook, in the Litchfield Hills, 

 Connecticut, I noticed many specimens of Polistes metricus Say 

 infested with Xenos (Acroschismus) wheeleri Pierce and I at once 

 began to collect them.^ 



In ten days during the latter part of August I gathered one 

 thousand specimens of the Polistes from flowers ot the golden 



1 Contributions from the Entomological Laboratory of the Bussey Institution, Harvard University 

 No. 20. 



2 There mav be some doubt about the specific names of the host and parasite here mentioned. I 

 have called the wasp P. metricus as this is the name under which it is commonly known and because 

 our extremely variable species of Polistes are in a state of great taxonomic confusion. Miss Enteman, 

 who has studied them very extensively ('04), would probably refer my specimens to P. pallipes Le- 

 peletier, while others would be inclined to regard them as belonging to P. fuscatus Fabricius. Brues 

 ('09 ) and I had identified the parasite as Xenos peckii Kirby, but Pierce ('08), regards it not only as speci- 

 fically, but also as generically distinct. He has given it the name wheeleri and placed it in a new genus 

 (Acroschismus) because it has the oedeagus" considerably dilated at the base, arising between two claws," 

 whereas Kirby's species is placed in another new genus, Schistosiphon. because it has the oedeagus 

 "cleft at the apex." The old genus Xenos of Rossi he restricts to the Eumpean species (vesparum 

 Rossi and jurinei Saunders). Although these generic distinctions may prove to be valid, I shall use 

 the old name Xenos in the present paper.) 



THE J01;RNAL of experimental zoology, vol. 8, NO. 4. 



