INSECTA. 349 



developed, and has above four membranous valves; below it is 

 nan-owed in shape of a funnel, and usually is introduced into the 

 next stomach by iiivagination. 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 larvae of the wasps, according 

 to RAMDOHR, there is nothing but a large blind stomach present ; 

 also in the pupae of the bees there is no anus; but these have an- 

 terior to the stomach a narrow oesophagus, 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 oesophagus lies very close to the first. In the 

 thorax there are ordinarily only two ganglia, of which, the posterior 

 is large ; in Athalia centifolice 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 Neuroptera. 

 Some of them by their larvae approximate to the butterflies ; and 

 some butterflies (Sesia) shew a great similarity with hymenopte- 

 rous insects. However, beyond doubt, the Hymenoptera have the 

 greatest affinity with the two-winged insects, and we believe that, 



