574 INSECTA— ORDER HYMENOPTERA. 



excrescences called galls on various plants, especially on the oak and rose 



though many of the smaller species are parasitic ; the groups 



Habits. generally classed together roughly as ichneumons, though 



they really include several very distinct families, are parasitic 



on other insects ; the burrowing and solitary wasps are carnivorous, the 



social wasps and the ants are omnivorous, and the bees feed on the pollen 



and honey of flowers. 



The ants, bees, and wasps, and the termites, or white ants, which greatly 

 resemble them, but which belong to the order Neuroptera, far surpass all 

 other animals in intelligence, and are the only creatures known to scientific 

 men which have developed any phases of social life and civilisation at all 

 resembling our own, and this is especially true of the ants. 



The Hymenoptera are probaVjly the most numerous of all insects in number 



of species, for although only 36,000 species have yet been described, a much 



smaller number than either the Coleoptera or Lepidoptera, yet 



Number of we have considerably more than 3,000 species in England, a 



Species. greater number than is known of any other order, and fully 



half of these belong to the parasitic groups, which only one 



or two entomologists have taken the trouble to study at all, and many of 



which are of very small size, some, indeed, being the most minute of all 



known insects, and there is no reason to doubt their being proportionately 



as numerous in other countries as in our own. 



The Hymenoptera are divided into two principal sections : the Terebrantia, 



or Boring Hymenoptera, in which the ovipositor is modified into a boring 



. apparatus; and the Aculeata, or Stinging Hymenoptera, in 



^'^^^tef™*'^ which it is modified into a sting. In the Terebrantia the 



irp \ r \ trochanter, or small hinge-joint which separates the coxa, or 



hip, from the femur, or thigh, is generally double, while in 



the Aculeata it is generally single ; but this is not an invariable character. 



The first division of the Terebrantia consists of the Serrifera, including, 

 the families Tenthredinicke and Siricidce, or saw-flies and wood-wasps. 



The TenthredinidiE are divided into several sub-families, in some of which 

 the antennse are short, and strongly clubbed at the end, like those of a 

 butterfly. The commonest of these species in England is 

 Saw-FUes Triehiosomn lucorum (Linn.), which is a blackish hairy 



{Tenthredinidce). insect, measuring rather more than an inch in expanse, 

 with transparent wings bordered with brown. The twenty- 

 two-legged larva feeds on hawthorn, and constructs a very solid brown 

 egg-shaped cocoon. It belongs to the sub-family Cimbicina;. Another very 

 interesting sub-family is that of the Perginie, 

 which are found in Australia, and have 

 short, club-shaped antennoe ; the species 

 are mostly black and yellow, and smaller 

 than Tricliiosoma, though some of them are 

 greenish, and about the same size. Their 

 black larv;e have only six true legs, no 

 prologs being developed, and they feed 

 gregariously .on gum-trees 

 Habits of Per^a. (Eucalyptus). In some 

 species, the female is said 

 to tend the young larviu after they are ^''J- 52.-Saw-Flt (rrictooma 

 , , , , ■' 111-. i • i_i htcorum). Nat. size, 



hatched, an unusual hanit, except in the 



case of social insects. The number of ioints of the antennse varies in the 



