INTERNAL GENERATIVE ORGANS OF THE MALE. 663 
utriculi majores and utriculi breviores. The former are milk 
white and surround the latter, which are more or less trans- 
lucent. Sections through this organ show that the utriculi 
majores are precisely similar to the paragonia of other insects, 
whilst the utriculi breviores differ in no way from the glands 
which are recognised as the testicle in the majority of insects : 
they contain sperm-cells and sperm in all stages of develop- 
ment. The vas deferens divides into two main branches at its 
anterior end, and each of these terminates in a number of both 
kinds of utriculi—so that, except in the nature of their con- 
tents, the utriculi majores and breviores are apparently iden- 
tical and are morphologically similar. 
Rajewsky [828], in 1875, published a paper in Russian, in 
which he describes what he regards as the true testes, and he con- 
siders the whole of the utricules of the mushroom-shaped body 
as vesiculee seminales. The testes described by Rajewsky un- 
doubtedly exist in the immature male, and are present in the 
adult male in an exceedingly atrophied condition, so that it has 
been concluded that the testes undergo atrophy in the adult 
male. It has been supposed that the mother cells of the sper- 
matozoa are formed in the glands which Rajewsky regards as 
testes, and descend into the utriculi, where they undergo 
further development. If this were really the case it is re- 
markable that no sperm-cells are ever found in the utriculi 
majores, and it seems to me that the supposition is exceed- 
ingly improbable. On the other hand, it may be that the 
glands of Rajewsky are really the more anterior follicles of 
a testis, and this more especially as they are persistent in 
Blatta Germanica, and are functionally active in the adult 
insect. 
Functions of the Paragonia——The secretion of these glands 
coagulates with great rapidity in the ejaculatory duct, or in the 
vagina of the female insect, and is apparently concerned in the 
formation of spermatophores. In the Orthoptera, in which 
paragonia are very largely developed, the spermatophores are 
usually of large size, and only one or two are discharged, and 
either attached to the exterior of the sexual orifice of the 
