THE OAK-EGGEE MOTH. 479 



fact, in eveiy place which affords shelter to the cateipillai'. 

 Nothing is easier than to procnre the insects from the cocoons, 

 as the yellow mass needs only to be pat into a box, with a piece 

 of gauze tied over it by way of a cover. Nearly every cocoon will 

 produce its ichneumon, and as the little creatures are not strong- 

 jawed enough to bite through the gauze, they can all be secured. 

 There are many species of Microgaster ; but those which have 

 been mentioned are the most important, and make the most 

 interesting habitations. 



The large oval cocoon was brought from New South Wales, 

 and is evidently the produce of some lepidopterous insect, pro- 

 bably a moth allied to the silkworm. Upon the larva which 

 constructed the cocoon an ichneiunon has laid her eggs, and tiie 

 consequence has been that the caterpillar has been imable to 

 change into the pupal condition, but has succumbed to the 

 parasites which infested it. These insects are not of minute 

 dimensions, like the Microgaster, but are tolerably large, and in 

 consequence can be but few in number. The cells are very 

 irregular in shape, and are not rounded like those of many 

 Ichneumonidse, but have angular edges. 



In this, and in one or two other examples which are shown in 

 the illustration, the reader will note a peculiarity in the develop- 

 ment of the parasite. The Microgaster larvae emerge from the 

 caterpillar just before it undergoes its change into the pupal con- 

 dition, and effectually prevent that change by IrilliTig the creattire 

 in which they had been nurtured. But, in many instances the 

 ichneumon larva delays its escape until the caterpillar has com- 

 pleted its cocoon, and in some cases waits imtil the change into 

 the pupal state has been achieved. In the present example, the 

 larva has permitted the cocoon to be made, and then killed the 

 caterpillar, the reason of this delay being that the cocoon is very 

 firm and strong, and affords an impregnable shelter to the 

 parasite. The names of the Parasites are placed beneath the 

 cocoons. 



WiTHm the same case there are several cocoons in which a 

 similar calamity has befallen the caterpillars which made them. 

 There is. for example, a cocoon of the Oak-Eggee Moth {Lasio- 

 campa gwrcu^, the interior of which resembles that of the insect 

 which has just been described, except that the cells of the parasite 



