CONVERGENCE OF COLORATION BETWEEN 



AMERICAN PILOSE FLIES AND 



BUMBLEBEES (BO MB US). 



E. GABRITSCHEVSKY, 



RESEARCH FELLOW OF THE INTERNATIONAL EDUCATION BOARD, 

 COLUMBIA UNIVERSITY, NEW YORK. 



THE EUROPEAN AND ASIATIC GROUP OF Vohicella Bombylans. 



In a previous paper, in which the heredity of color variations 

 in the European fly Vohicella Bombylans has been described, an 

 attempt has been made to show the striking resemblance in 

 coloration between various flies of the families Syrphidae, Asilidse, 

 Tabanidae, (Estridx and Bombylidx with various bumblebee 

 species which inhabit the same geographical regions. 



The study of those analogous color patterns which appear both 

 amongst flies and bumblebees is interesting from a genetic point 

 of view and bears on the problem of mimicry in animals. 



The black V. Bombylans (PI. L, Figs, i, d\ 9 ; 2, 9 ; 3, 9 ) 

 with its fulvous bands on the last abdominal segments has exactly 

 the same coloration as the common European Bombus lapidarius, 

 B. confusus, B. rajellus, B. mastrucatus, etc. The other variety, 

 V. hxmoroidalis (PI. L, Figs. 4, 5), is almost indistinguishable 

 from many other Bombus species, as for example B. agrorum, B. 

 vorticosus. The third variety of the V. Bombylans, the V. B. var. 

 plumata (PL L, Figs. 6, 6 , 9 ; 7, 9 ) with its characteristic white 

 hairs on the last abdominal rings, is extremely like B. hortorum, 

 B. lucorum. Vohicella bombylans (and its varieties), if really pro- 

 tected by her mimetic coloration, may be supposed to creep 

 unobserved into a Bombus nest to lay her eggs there on the wax- 

 combs. More often however the fly puts her eggs on the grass 

 and moss, which covers the Bombus nest. This of course can 

 only be performed with a Bombus species which builds its nest on 

 the ground, not under the ground. In localities where many 

 Bombus colonies of this kind are present the Vohicella flies are also 

 found in large quantities. The larvae of Volucella feed on wax, 



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