212 THE HUMBLE-BEE vu 
Edinburgh, in 1895; it has also been found freely 
around Rugby by the Rev. F. D. Morice, and 
in the neighbourhood of Belfast by Mr. H. L. 
Orr. In East Kent, however, I have taken no 
specimens except one giant male, nor have 
I found it on collecting excursions in West 
Kent, Sussex, and Surrey. Probably, therefore, 
it is rare in the south-east of England, but 
common in many places in the midlands and 
north, 
It has been taken in Cornwall, and a male of 
the yellow-tailed variety has been sent me by 
Mr. Cunningham from Cargill in Perthshire. 
I have seen examples (all white-tailed) from 
several places in Ireland. 
One would expect Ps. dzstznctus to breed in the 
nests of Bomébus lucorum, and this supposition is 
favoured by the fact that at Edinburgh and Belfast 
B. lucorum is much more abundant than BL. ¢er- 
restris. To settle the question Mr. Orr kindly 
sent me a living dzstznctus queen from Belfast on 
June 6, 1911, and I introduced her to a small 
lucorum colony whose queen was dying. She 
made herself at home immediately, and subse- 
quently produced 48 young, 34 being males and 
14 females; the females were produced after the 
males. 
It is remarkable in how many details the dif- 
ferentiation between Ps. vestalis and Ps. distinctus 
corresponds with that which exists between their 
respective hosts &. ¢errestris and lucorum; for 
