90 MEMOIR OF 



butterfly, (according to the usual course of 

 nature,) should produce sometimes one, some- 

 times two, or three, and sometimes a whole swarm 

 of ichneumones. I have observed this anomalous 

 production in a great many sorts of caterpillars, 

 both hairy and smooth ; in several sorts of mag- 

 gots, and which is most strange, in one water 

 insect. When there come many of these ichneu- 

 mon maggots out of the body of the same cater- 

 pillar, they weave all their thecas together into 

 one bunch, which is sometimes wound with web 

 about it just like a bag of spiders' eggs; but I 

 dare venture to answer Mr Lister's tenth quaere, 

 page 21772 of the Philosophical Transactions, 

 negatively, that none of them feed on spiders' 

 eggs, but it is the similitude of those thecas con- 

 globated together to the eggs of spiders, that hath 

 occasioned this conjecture. One of the green 

 caterpillars common on the heaths in the north, 

 went so far on to her natural change that she 

 made herself up into a great theca, almost of the 

 shape of a bottle, which was filled with a swarm 

 of ichneumones. And 1 have observed, in one or 

 two other sorts, that from the very aurelia itself 

 hath come an ichneumon ; while it is very odd 

 that the caterpillar, stung and impregnated by the 

 ichneumons, should yet be so far unhurt and 

 unconcerned as to make herself a theca, and to be 

 turned into an aurelia. This year, being in com- 

 pany with an ingenious neighbour, we observed 

 one haling a large green caterpillar, much bigger 

 than herself, which, after she had drawn the 



