ANTS, BEES, WASPS, AND THEIR KINDRED 1 1 1 



many native species, belong to the families Ichneu- 

 wonida and Bmconidce.. They are separated in accord- 

 ance with the number and arrangement of the " cells " 

 (areas enclosed by veins) in the fore-wing ; but as the 

 species are all extremely similar in their general 

 structure and habits, we may treat the two families as 

 one. Ichneumons are slenderly built insects, with 

 long antennae. They lay their eggs either in or upon 

 the larvae or pupae of other insects Lepidopterous 

 caterpillars being most commonly chosen for the 

 purpose. The females are provided with ovipositors, 

 which are often conspicuous, sometimes of great 

 length. Among the latter are species which attack 

 wood-boring larvae ; and it is stated that some of these 

 will drive their ovipositors through a considerable 

 thickness of timber in order to reach their victims. 

 As a rule, ichneumon grubs do not seriously affect the 

 vitality of their " hosts " until their own development 

 is almost complete. Indeed, the host often preserves 

 sufficient strength to assume the pupal state, and 

 occasionally completes its metamorphosis, though this 

 is rare. Usually it perishes soon after the parasites 

 have left it to spin their own cocoons. One of the 

 commonest Braconid ichneumons is known as Micro- 

 gaster glomeratus. It implants its eggs in the cater- 

 pillars of the large- white butterfly 1 in such numbers 

 that when the victims are full-grown their skins may 

 be literally packed with fat Microgaster grubs. The 

 latter eventually escape, and spin their small yellow 

 cocoons in a mass round the body of the larva that 

 they have done to death. " Although such parasitism 

 raises a feeling of repulsion (writes Dr. Sharp), yet 

 there is reason for supposing that there may be little 

 1 Pieris brassica. 



