INSECTA. 349 
developed, and has above four membranous valves; below it is 
narrowed in shape of a funnel, and usually is introduced into the 
next stomach by invagination. This stomach is cylindrical, of vari- 
ous length, and ordinarily divided by transverse folds as though 
into rings. The small intestine (beneath the insertion of numerous 
vasa urinaria) is narrower than the stomach, ordinarily not longer, 
sometimes even shorter than it; the rectum is wider again. The 
whole intestinal canal has no very considerable length ; in many it 
is little longer than the body. In the larvee of the wasps, according 
to Rampour, there is nothing but a large blind stomach present ; 
also in the pupz of the bees there is no anus; but these have an- 
terior to the stomach a narrow cesophagus, and behind the stomach 
an intestinal canal terminating blindly. 
The air-tubes present in most hymenopterous insects sacciform 
expansions. In the bees and wasps even the lateral primary stems 
in the abdomen are widened into large air-sinuses. The nervous 
system exhibits different modifications in the different families. 
The first nervous ganglion, the cephalic ganglion, is usually large, 
since the optic nerves especially are much developed. The second 
ganglion under the esophagus lies very close to the first. In the 
thorax there are ordinarily only two ganglia, of which, the posterior 
is large ; in Athalia centifolie NewPort found three. The abdomen 
has from four to seven ganglia, ordinarily, however, only five or 
SIX. 
This order does not contain any particularly large species, although 
in the mean they are somewhat larger than the Diptera. Only a 
few species are bright coloured; the colours most frequently occur- 
ring are brown, black and yellow. The species are uncommonly 
numerous, so that in this respect the order of Hymenoptera is per- 
haps inferior to the Coleoptera alone. Most of them indicate a very 
remarkable instinct, and many construct their nests artfully. There 
is one species from which man derives a great and immediate advan- 
tage, and which he has transported with himself to different regions 
of the globe. We mean the honey-bee, of whose history we shall 
shortly treat in the sequel. 
In their metamorphosis these insects correspond with the beetles ; 
in this respect they differ entirely from most of the Newroptera. 
Some of them by their larve approximate to the butterflies ; and 
some butterflies (Sesia) shew a great similarity with hymenopte- 
rous insects. However, beyond doubt, the Wymenoptera have the 
greatest affinity with the two-winged insects, and we believe that, 
