238 NORTH AMERICAN INSECTS. 



form themselves into white silken cocoons, which resemble 

 rice-seeds in appearance, and which cover the whole body 

 of the emaciated and dying caterpillar. 



Very minute ichneumons, scarcely visible to the naked 

 eye, deposit their eggs in the eggs of different lepidopterous 

 insects, and from these the perfect ichneumon issues about 

 three weeks after. 



The family of Ichneumon-wasps is immensely large in all 

 parts of the world. In 1829 the Swedish entomologist, 

 Gravenhorst, published three large volumes on " Ichneumon- 

 ologia Europaa,'' to which Professor Nees, of Bonn, made a 

 considerable addition ; but if one should undertake to de- 

 scribe the genera and species of the American, Asiatic, 

 African, and Australian ichneumons, of all of which very 

 little is known, he would occupy more than twenty large 

 volumes. 



The largest ichneumon of this country is the Pbipla 

 LuNATOR (Fig. 66), the body of which is about one inch 

 and a half, and the ovipositor three inches long. One 

 would naturally suppose that so long an organ, with the 

 two side bristles, which serve as a scabbard, would be 

 very burdensome to this insect; but by watching her 

 movements he would soon see with what ease and skill 

 this little creature manages that instrument, and by means 

 of it introduces her eggs into those larvae which are con- 

 cealed in deep holes under the bark of trees, or in decayed 

 wood. 



We have before spoken of the handsome green caterpillar 

 of the Asterias Butterfly, represented in Fig. 30, and found 

 so commonly upon the leaves of all the umbelliferous plants. 

 Our attempts to raise the handsome Papilio asterias from 

 these caterpillars have often been frustrated by a species 

 of ichneumon which, stinging the caterpillar, grows within 

 its body until it forms its cocoon, when it destroys the 

 chrysalis, and then emerges from the cocoon instead of the 



