ICHNEUMON PLY. 163 



neously eat their way out of the doomed creature, 

 and immediately spin for themselves a number of 

 bright yellow cocoons, among which the dying cater- 

 pillar is often hopelessly fixed. Sometimes it has 

 sufficient strength to escape, but it never survives. 



In the later summer months, these cocoon masses 

 may be seen abundantly on walls, palings, and 

 similar spots. 



Plate I, fig. 3, shows the Brimstone Butterfly, one 

 of the first to appear as the herald of spring. 



