1894.] Entomology. 895 
parasitic species, all of which are strong and robust, and ordinarily 
neither need nor possess any such protection as a mimetic resemblance. 
It is well protected on the body by strong hairs, answering, to some 
extent, the purpose of spines, and is very strong on the wing; it is 
very large, too, many specimens being 8 or 9 lines long. It, however, 
occurs at this time (March) when other insects are scarce, and it must be 
conspicuous and so tempt its foes, and although common on this par- 
ticular occasion at Wyre Forest, I do not think it is usually a common 
species, at least, I never saw it before; altogether, although it does not 
answer the usual requirements of a mimetic species, yet there are ob- 
viously good reasons why a resemblance to the strong and usually un- 
molested Bombi would be an advantage to it. We accordingly find 
that it does possess some such resemblance, though imperfect, and it is 
just this imperfection which is its most interesting feature, and it is to 
some extent the reason for these notes. 
* Many or all of the opponents of the theory of mimicry urge very 
strongly the difficult question, how does the resemblance arise? In 
early stages it can be of no use to its possessor. But here, I think, we 
have a case showing how mimicry may arise, and even the early stages 
be of use. The Tachinide do not, as a rule, resemble in the least de- 
gree any Hymenoptera, they are quite unlike bees. The Echinomyia 
are a genus of unusually large and well developed Tachinids, some of 
which (fera and ferax for example) are simply ordinary Tachinids in 
appearance, though unusually large, and quite unlike bees; they are 
summer species; Ursina, however, a spring species, though closely al- 
lied to these others by a comparatively slight alteration in color, a 
development rather than an alteration, and the inerease of its hairs in 
number and size, at once and unexpectedly somewhat resembles Bom- 
bus museorum, and almost certainly must derive some protection from 
even this superficial resemblance, at a time when food is being so 
eagerly sought by insect foes. It only needs a still further increase in 
hairiness, and to fold its wings over its body, and it would be an 
almost perfect mimic; and supposing its nearest allies to be lost, we 
should wonder how the early stages arose. 
Description of a New Pelecinus from Tennessee.—The 
genus Peleeinus forms a peculiar family allied to the Proctotrupidze, in 
the Antigynea, among the highest Aculeate hymenoptera. The costal 
vein in rare instances is not developed, showing a transition to the 
higher non-aculeate monotrocha or Hymenoptera minuta. The larval 
habits are unknown, although the imago has been observed issuing 
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