160 Psyche [December 



only pair I ever took in co]). belonged to the two extreme forms. 

 There can be but little doubt that the form bombylans mimics 

 Bomhiis lapidarius, while the form plumata mimics Bomhus terres- 

 tris. It is only natural that with such a remarkable dimorphic 

 species pairing indiscriminately, and mimicking a genus such as 

 Bomhus in which there are numerous other color forms, various 

 other color variations should frequently occur, and a vast number 

 of these have been described as distinct species or have received 

 varietal names. 



"If it be once recognized that all the European species which are 

 densely pilose belong to one species, concerning which I hold no 

 possible doubt, then the synonymical list in this book will answer 

 for itself, though I may add that I possess several specimens of 

 the North American V. fascialis Will, and I cannot distinguish any 

 structural distinction, so that I expect both V. facialis Will, 

 and V. evecta Walker are also synonymous." 



Verrall further states: "A remarkable instance of this mimicry 

 occurs in one very common species, V. bombylans, which (I estimate 

 without accurate observation) imitates Bomhus terrestris (and 

 its allies) for about 60 per cent., but imitates B. lapadarius for 

 about 38 per cent., while the other 2 per cent, may be of almost 

 any Bombus coloring." 



Another interesting feature in connection with this matter is 

 that the inquiline bee Psithyrus rupestris so closely resembles 

 Bombus lapidarius as to be scarcely distinguishable while P. 

 vestialis is banded similar to B. terrestris. In this country our 

 species of Psithyrus closely resembles our species of Bombus and 

 no species resembling P. rupestris is found here. 



From the above we might infer that the typical V. bombylans is 

 absent in America because there is no bumble-bee here like the 

 Bombus lapidarius of Europe. On the other hand our forms 

 resemble more closely the various species of Bombus found here 

 than the European species do. Thus we have forms with seg- 

 ments three to five of the abdomen with entirely black pile, 

 resembling Bombus pennsylvanicus, etc., and others with a fulvous 

 band on the third segment resembling Bombus ternarius. 



Regarding their habits Verrall says: "Probably all the European 

 species of this subfamily are scavengers in the nests of large 

 aculeate Hymenoptera, feeding on the diseased pupse, etc., but not 



