110 NATURAL HISTORY OF WASPS. 
make the number in the female humble-bee twenty- 
three only, and in the Ligurian honey-bee, seventeen 
in the male, twenty-three in the worker, and eighteen 
and twenty on the two sides of the female in my 
cabinet. They are seen to greatest advantage in the 
humble bee, but they come out very beautifully, like a 
rope-moulding, in the hornet, as shewn in the accom- 
panying sketch. Corresponding to the row of hooklets 
Fig. 5.—Diagram of the hooklets on the hind wing of the hornet, 
seen enon the lower surface. 
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on the hind wing is a crest on the posterior edge of the 
fore-wing, forming a ledge beneath which the ends of 
the hooks catch. The points of the hooks turn up, 
and the corresponding ledge or flange turns down to 
meet them. 
The locking of the wings in Lepidopterous insects 
is effected by a different mechanical arrangement to 
that which obtains in wasps and bees. Thus: parallel 
to the front edge of the hind wing, and sprmging 
from its root, is a long, strong bristle. Near the root 
of the fore-wing, a slight horny process, somewhat 
hooked, rises from one of the nervures. The bristle 
is readily caught by this, or by the tuft of hairs which 
in some species answer the same purpose, so that the 
locking or unlocking is effected ina moment. The 
apparatus varies in form in different species, it is 
found chiefly among the moths; my own observations 
