OF NORTH AMERICA. 89 



This species is abundant in the neighborhood of San Francisco, 

 feeding on the various species of oak. The larva is nocturnal in its 

 habits, and in the day time may be found crowded into holes and cavi- 

 ties (generally in families) and often in places where it seems scarcely 

 possible for them to penetrate. The imago is much rarer than the 

 abundance of the larva would indicate, as the latter are very subject to 

 the attacks of ichneumons, chiefly of small size. 



