41 8 William Morton Wheeler 



Instead of stopping to review the various examples of parasitic 

 castration cited by Giard in his paper of 1888, and in many of 

 his later publications, it will be preferable to describe as brieflv 

 as possible a number of selected examples, especially some that 

 have come to light more recently among insects. The stylopized 

 Polistes and Andrenae, having been adequately described in the 

 first part of this paper, will be omitted. 



Grassi and Sandias ('93) describe a remarkable case of parasitic 

 castration in termites. They find that worker and soldier ter- 

 mites have the intestinal caecum, which occupies much of the ab- 

 dominal cavity, distended with enormous numbers of parasitic 

 Protozoa belonging both to the Ciliata (Dinonympha, Pyrsonym- 

 pha, Trichonympha) and to the Gregarinida. The Ciliata have 

 been studied by several authors, notably by Leidy i^TJ^ '81), 

 Grassi ('85), Kent ('85), Porter ('97), and Dodd ('06). In ter- 

 mites infested with these parasites the reproductive organs, both 

 male and female, remain small and undeveloped, apparently as 

 the result of the pressure exerted on them by the distension of 

 the caecum. The parasites are absent in the very young termites 

 and in the sexual forms, which are fed on saliva. Grassi and Sand- 

 ias infer that the Protozoa must either be killed off or, at any 

 rate, prevented from living and growing in the alimentary tract 

 of saliva-fed mdividuals. These investigators are mclmed, there- 

 fore, with some reservations, to regard the development of the 

 two sterile castes in termites as the result of infection w^ith pro- 

 tozoan parasites. This infection is, of course, readily brought 

 about as the workers and soldiers are not fed on saliva like the 

 sexual forms but on dead wood and on the faeces of individuals 

 belongmg to the same castes. 



The researches of Grassi and Sandias have received a certain 

 amount of confirmation from Brunelli ('05), who finds that queens 

 of Calotermes flavicollis and Termes lucifugus sometimes become 

 infested with the parasitic Protozoa, and that when this happens 

 the young oocytes in their ovaries degenerate. Calotermes queens 

 are more susceptible to this form of castration then the queens of 

 Termes. Brunelli explains the winged soldier observed by Grassi 

 and Silvestri's ('03) 48 workers of Microcerotermes struncki with 



