124 



ZOOLOGY, 



Wings, four, all membranous, with relatively few 

 veins (Figs. 61, 90). Metamorphosis complete ; larvae 

 very various; pupae free (p. 93). The female usually 

 ])ossesses an ovipositor, the structure 

 of which varies a great deal, and 

 which serves in many species, not 

 only for egg-laying, but also for pro- 

 tection (digging wasps); in others 

 exclusively for offence or defence 

 ("stings" of bees and wasps), while 

 the same opening serves for the pas- 

 sage both of eggs and excrement. 

 The abdominal glands, secreting a 

 sticky substance by which the eggs 

 are attached, are modified into poison- 

 glands in those Hymenoptera which 

 possess a sting. In those forms 

 FiG.87.— Head of Honey wherc the ovlpositor is not modified 

 Bee. A, compound j^j-Q g, stiug, it is uscd for piercing, 



eyes ; a, Bimple eyes ; 6' . -f 6' 



z. bitmg, or sawmg. 1 he Hymenoptera 

 with saw-like ovipositor first make 

 an opening in wood or in a leaf by 

 means of the saw-teeth in its edge, 

 and then lay an egg in this hole. 

 Many Hymenoptera (all digging wasps, gold wasps, 

 ichneumon flies, and gall flies — several true bees 

 and wasps) live alone, or in pairs. Others form 

 colonies, in which division of labour is always so far 

 carried out that there are reproductive individuals 

 and workers. The former (males and females; in 

 colonies of bees — "drones" and "queen") are only 

 present in small numbers in any particular colony. 

 They live merely for the perpetuation of the species. 

 At most the males seek their own food, while the 

 females are usually fed by the workers. Workers, on 

 the other hand, are individuals in which the (female) 

 reproductive organs remain in a low state of develop- 

 ment, so that they are sterile. They seek food for the 



eyes; 



Ji% antenna ; 

 tongue (under lip) ; 

 6, labial palps; Fz, 

 elongated maxillaa ; 

 the mandibles and 

 upper lip remain 

 short. 



