THE EUMENIDAE 311 



behavior. They find that "Odynerus annulatus and 0. gemi- 

 nus occur in the same locality, but differ widely in habits. 

 Annulatus provisions its nest with the larva of Loxostege 

 sticticalis (Pyralidina), geminus with the larva of Pholi- 

 sora catullus (Hesperidae) although the larva of L. sticti- 

 calis was common for geminus." 



We have found wide variation in the number of these 

 caterpillars used by O. geminus; all the way -from four to 

 fourteen in the cells. This difference must be due to faulty 

 instinct on the part of the mother wasps. We do not see 

 how the larvae could thrive equally well on such varied 

 provision. In rearing some larvae from egg to adulthood, 

 we offered them additional caterpillars when they had eaten 

 all that their mothers had provided for them, and they 

 gladly accepted and devoured many more. 



A study of the longevity of a large number of these eater-- 

 pillars which had been entombed in the cells showed great 

 variation. 



Died after 7*4 months I 



Died after 54 days 2 



Died after 18 days 5 



Died after 12 days i 



Died after 9 days 4 



Died after 8 days 2 



Died after 7 days 2 



Died after 5 days 5 



The great majority of them lived from five to eighteen 

 days after having been exhumed ; this is not of course ex- 

 actly the same as the length of time they survived the 

 stinging, but corresponds roughly to it. They were for 

 the most part very active when the space permitted it, 

 squirming and writhing vigorously and doing everything 

 but walking away. One seeing this activity could under- 



