118 [May. 



in a stylopized bee tliat is caiTvIng a good load of pollen (a verv rare 

 circumstance) and also in some species of Andrena in which, as here- 

 after mentioned, the pollinigerous apparatus is less deteriorated by 

 stylopization than in those hitherto worked at, with the condition that 

 ordinarily results from the parasite. 



Pairing of the sexes is beyond doubt frequent in stylopized bees. 

 On the one day that I was able to make any observations last year, 

 I took two pairs of A. spreta in cop, in which one of each pair was 

 stylopized. In America, Crawford in the case of Andrena crawfordi 

 noticed three cases in four days, and in one of these both J and $ 

 >vere stylopized. As comparatively few bees of the total number seen 

 are stylopized and few also are taken in copula^ it cannot be expected 

 that one would very frequently notice such cases. We may conclude 

 that though the female bee when styloj^ized is sterile except perhaps in 

 very exceptional cases, not yet demonstrated, the (S is rarely if ever 

 oasti-ated. When very badly injui-ed by the attack or emergence of 



rT StyIo])s, male bees may be so incapacitated as to be scarcely able 

 to fly and are naturally incapable of pairing, but such cases are quite 

 exceptional, and even in some of these I have found no appreciable 

 alteration of the internal reproductive organs. In the case of one such 



<5 of A. trimmerana, however, there was a disparity in size of the 

 genital glands, but on both sides spermatozoa were perfectly produced. 

 It may be that such disparity may also occur sometimes in non- 

 stylopized examples. 



The external changes due to stylopization are more or less well 

 known to all collectors of bees, and an admirable summary of the chief 

 or most conspicuous of these is given by Edward Saunders in his 

 *^ Synopsis" of British Aculeata (Tr. Ent. Soc. Lond. 18S2, pp.228, 

 229). More minute details are considered by Perez in his work already 

 referred to, published in 18S6 (Act. Soc. Linn. Bordeaux, xl, p. 21). 



One may note m a general way that stylopization generally affects 

 such external characters as are subject to more or less variability in 

 healthy examples. Thus a decrease or increase in length or amount 

 of clothing, change in the colour of the facial hair {e. g. from brown to 

 black), variation in the size of the head, etc., may often occur in healthy 

 bees. Change of colour of the white or yellow clypeus of the S does 

 not occur in non -stylopized bees in this country ; but one of om* species, 

 A. Jiumilis x-av. fulvescens Sm., is found with both white and black face 

 on the Continent. The stylopized male of A. clirysosceles sometimes 

 has the clypeus black also, and it is interesting to note that healthy 



