2 [January, 



viscera, often almost[entirely concealing them. The most surprising 

 fact to me was that the internal effects of its attack should be 

 apparently so slight ! 



The generative organs were examined in a number of male bees : in some eases 

 the armature was somewhat smaller and paler than in healthy individuals. This 

 change is quite in accordance with the effects seen in the* external cuticle generally, 

 and, at any rate, so far as these two species are concerned, I incline to think that the 

 changes produced are mainly cuticular. In all the S specimens that I dissected, the 

 vesiculcB seminales were found to contain active spermatozoa. On mounting in 

 water their movements could be plainly seen through the walls. Very often, how- 

 ever, on contact with the water, the vesiculce are burst, their shape is changed, 

 becoming constricted, their size is diminished, and the contents are carried away to 

 a distance in the currents set up. When set free the spermatozoa continued for 

 some time in active movement. Their form was normal, and they behaved in the 

 usual manner when treated with staining fluids. 



The testes, consisting of several tubes very closely bound together, and somewhat 

 difficult to separate, contained cells with one or more nuclei ; probably they had 

 ceased to be of functional importance after the full development of the bee and the 

 formation of the spermatozoa. 



As to the female bees I do not feel certain tliat in any of the few specimens 

 examined the contents of the ovaries were fully developed. Whether the ova 

 would have developed further I do not know ; mAxij healthy females had the ovaries 

 in exactly a similar condition. The freshly emerged S l^as the spermatozoa already 

 fully developed, but the ova of the $ develop largely after its emergence. Hence 

 the difficulty in deciding without the examination of many specimens. 



The digestive tract appeared to me to be normal in both sexes of the bees 

 examined. 



It is certainly a remarkable fact that stylopized individuals are 

 sometimes very considerably larger and finer specimens than the 

 ordinary healthy ones ! As far as the species I have named are con- 

 cerned, I see no reason to doubt the possibility of their being capable 

 of reproduction — at any rate, the males. 



Moreover, in the females the scopcB are often perfectly normal, in 

 spite of the parasite, and two of the specimens I caught in 1890 had 

 them well covered with pollen. One of these, a $ Jlalictus cylindricus, 

 had the ova as fully developed as a healthy hibernated specimen taken 

 at the same time. Those individuals in which the scopcB are aln^ost 

 entirely aborted, would, of course, if capable of fertilization, be quite 

 unable to collect the usual amount of pollen for their larvce. 



Whilst collecting the material for the above observations, some 

 interesting questions concerning the life-history of the parasites 



* These external changes have been discussed by Mr. Edward Saunders, Ent. Mo. Mag., 1889 

 p. 2S>3. 



