OF INSECTS. 
303 
there is no trace of them, except in the costal alone, 
which loses itself in a scarcely perceptible stigma.”* 
The value of the generic characters afforded by 
the modifications which the figure of the cells under- 
goes, may be inferred from the fact stated by M. 
Jurine, that he could, in most cases, determine the 
genus of a hymenopterous insect from the inspec- 
tion of the wings alone. 
As among the Hemiptera, the inferior wings are 
more or less closely united to the superior when in 
action, but this is effected by a different hind of 
mechanism. Along the anterior edge of the secon- 
dary wings is placed a series of very fine hooks, 
( [hamuli ,) wliicli attach themselves to the hinder 
margin of the primary pair, and a continuous sur- 
face of some extent is thus presented to the air. 
From the preceding details it may be inferred 
that the Hymenoptera possess great powers of flight. 
It is in fact one of the orders in which that power 
has reached its maximum ; all the necessary con- 
ditions being found united. The great distances to 
which bees fly in search of honey, often against a 
strong wind* are well known ; and even when they 
are loaded w r ith pollen, or other substances — with 
“ treasures sucked from buds and bells” — the rapidity 
of their aerial movements appears in no degree re- 
tarded. 
The humming noise which many of them emit is 
not produced by any organs specially formed for that 
purpose, as among the Hemiptera and Orthoptera, 
* Intro, h TEntom. I. 368. 
