354- AFFECTION OF INSECTS FOR THEIR YOUNG. 



and the exterior flat sides scored and toothed), which 

 play alternately ; and, while their vertical effect is that of 

 a saw, act laterally as a rasp. When by this alternate 

 motion the incision, or cell, is made, the two saws, re- 

 ceding from each other, conduct the egg between them 

 into it a . The Cicada, so celebrated by the poets of an- 

 tiquity, which lays its eggs in dry wood, requires a 

 stronger instrument of a different construction. Accord- 

 ingly it is provided with an excellent double auger, the 

 sides of which play alternately and parallel to each other, 

 and bore a hole of the requisite depth in very hard sub- 

 stances without ever being displaced. 



The construction of the sting or ovipositor with which 

 the different species of Ichneumon are provided, is not 

 less nicely adapted to its various purposes. In those 

 which lay their eggs in the bodies of caterpillars that feed 

 exposed on the leaves of plants it is short, often in very 

 large species not the eighth of an inch long : having free 

 access to their victims, a longer sting would have been 

 useless. But a considerable number oviposit in larvae 

 which lie concealed where so short an instrument could 

 not possibly approach them. In these, therefore, the sting 

 is proportionably elongated, so much so that in some 

 small species it is three or four times the length of the 

 body. Thus in Ichneumon Manifestator, whose economy 

 has been so pleasingly illustrated by Mr. Marsham b , and 

 which attacks the larva of a wild bee {Apis maxillosa) 

 lying at the bottom of deep holes in old wood, the sting 



1 Prof. Peck's Nat. Hist, of the Slug-worm, 1. 12. f. 12-14. Plate XV. 

 Fro. 21. 



b Linn. Trans, iii. 23. 



