CARNIVOROUS INSECTS 107 



Ichneumon -Flies. — The provision made for their young by 

 the large group of Ichneumon- Flies is still more remarkable, 

 for in this case the female deposits her eggs in the bodies of 

 insect-larvse, especially caterpillars. When these eggs hatch out, 

 an abundant food-supply surrounds them, in the form of the 

 stores of reserve material which are laid up for use when the 

 adult stage is gradually being shaped in the chrysalis. 



BEETLES (COLEOPTERA) 



A large number of Beetles are carnivorous in habit, and in 

 none of them is this more strikingly the case than in the Tiger- 

 Beetles (see vol. i, p. 367), of which the commonest British species 

 is the Field Tiger- Beetle {Cicindela campestris). This is an 

 extremely active insect, which can run with great rapidity, and 

 is possessed of considerable powers of flight. As is usually the 

 case in predaceous animals, the organs of sense are well developed. 

 The most characteristic structures present are the mouth organs, 

 which are obviously constructed on the same type as already 

 described for Cockroach (p. 102). The mandibles, however, are 

 slender but powerful-curved blades, the inner edges of which 

 present a series of sharp projecting teeth, and the biting -pieces 

 of the first maxillae are studded with strong bristles, while each 

 of them ends in a movable claw. The second maxillae are much 

 more closely fused into a lower lip than is the case in the Cock- 

 roach. These beetles are extremely fierce, and have even been 

 known to indulge in cannibalism. Staveley says (in British 

 Insects): — "The female has often been seen to deliberately dis- 

 member and eat her husband, though it remains a puzzle to 

 naturalists that the husband — an insect apparently equal to herself, 

 or nearly so, in size and power — should submit to this ". The 

 larva of the Tiger- Beetle is also predaceous, lurking in a vertical 

 burrow in the ground, and attacking small insects which happen 

 to pass. 



Ground- Beetles. — Most of the Ground -Beetles {Carabidci) 

 are carnivorous, and these include an enormous number of species 

 scattered all over the globe. The Violet Ground- Beetle (Carabus 

 violaceus) is often found in houses, where it preys upon crickets 

 and cockroaches. It is nocturnal in habit, unlike the Tiger-beetle, 

 which hunts its prey during the day. Some of the Ground- 

 Beetles excavate burrows, at the mouths of which they wait for prey. 



