THE 'lIYMENOPTERA. 1 65 



or less well developed. The mandibles are always strong, but 

 differ much in form, according to the habits of the species. The 

 jaws and the lower lip, which are usually rather short, elongate 

 in some kinds Avhich pump up honey, and they then form a kind 

 of trunk, which is doubled up against the thorax when it is not 

 wanted. The thorax is swollen out, as it were, and its integu- 

 ment is solid and dense, like a cuirass ; and the muscles which 

 produce the movements of the wings, and which arc attached to 

 it within, are very large and strong. The legs have moderate 

 powers ; and, although these insects are better able to walk than 

 the Lcpidoptera, still they cannot be called, in comparison with 

 others, either walking or jumping insects. Their best means of 

 locomotion are their wings ; and the insects fully understand this, 

 for even when they have to walk a short distance the wings assist 

 the legs, and help the not very heavy body to move along. The 

 only Hymcnoptcra that can be called true walkers are those that 

 have no wings, like the neuter ants, and their agility is very won- 

 derful. The legs are often provided with accessory structures, 

 and are, moreover, modified so as to enable certain species to 

 live particular lives. 



Most of these insects have a very movable abdomen attached 

 to the thorax by a very narrow waist, Avhich is notoriously small, 

 in the wasp tribe for instance. The females have a long and 

 slender tube at the end of the abdomen, which is of great im- 

 portance to them, either as an ovipositor or as a sting. The 

 weapon of offence is invariably formed by the same kind of 

 structures in all insects that possess it, and Lacaze Duthiers 

 has discovered it in a rudimentary condition even amongst the 

 Lcpidoptera. These structures are modified in various manners, 

 but the same end is always kept in view, and the resulting organ 

 is of the greatest importance. 



The Hymcnoptcra undergo complete metamorphoses. Some 

 larvae are usually soft and white, and, as they have no legs, they 

 look like worms ; but some exceptional kinds have small fore and 

 hind legs like caterpillars. Almost all the larvai, when they have 

 attained their full growth, shut themselves up in a cocoon, which 

 they make up with the silken stuff they are able to produce, and 

 then are transformed into pupae. 



