( Ixviii ) 



not bring these home, but I feel sure they were right. Still, 

 I cannot understand the uniform size of the $ $. The $ o 

 are all sizes, with occasional gigantic ones. The $ ? all uni- 

 form in most Andrena, with very rarely one about half the 

 proper bulk. 



" The most favourable (i. e. for variation) species to investi- 

 gate do not make compact colonies like clarkella, but burrow 

 singly, scattering over perhaps a whole field — I mean the 

 favourable species in this locality. A very easy one to inves- 

 tigate would be A. fulva, Schr., which produces gigantic Jo 

 freely in ' the Parks ' at Oxford and makes big colonies, but 

 unfortunately it is not here at all. Also our soil is not very 

 easy to dig in — an extraordinarily wet clay at the roots of 

 trees, where the clarkella were nesting. 



" I may chance on some better colony soon. I badly want 

 larvae of the bees Nomada (parasitic on Andrena). No one 

 knows whether both host and parasite lay eggs on the same 

 pollen mass, and the latter larva kills the other, or what 

 happens. The want of exact information as to the habits of 

 the cuckoo-bees is simply astonishing." 



Giantism in Male Bees, by Dr. R. C. L. Perkins. 



No one who has examined a considerable collection of bees 

 of the genus Andrena — or, in fact, of some other genera — 

 can have failed to notice the occasional occurrence of indi- 

 viduals of the male sex of gigantic size. This giantism has 

 been observed by me in nearly all our British species of 

 Andrena and probably occurs in all. Great variation in size, 

 whether this be in excess of the average or in decrease, is of 

 course a very familiar phenomenon in many insects, but 

 owing to the nature of the nutriment of the larvae and the 

 manner in which this is provided, it is of particular interest 

 in the case of the solitary bees. So far as we know the 

 amount of food stored in the bee's cell to serve as food for 

 the larva varies little, though certainly it is desirable that 

 accurate investigations should be made on this point. At 

 the same time the comparatively uniform size of the females, 

 excepting in special cases to be noticed, confirms the impres- 

 sion made on me by the examination of actual stored pollen 



