312 WASP STUDIES AFIELD 



stand at once why it might be safer for the delicate egg 

 to be fastened up to the wall by a strong thread than to be 

 dropped ruthlessly into a writhing mass like this, although 

 we suspect that in most cases it would survive. 



A few of the caterpillars showed exceptional longevity. 

 Two remained active for fifty-four days, and one aston- 

 ished us by continuing to live from September to the fol- 

 lowing April,- or seven and a half months. After the first 

 three months, it ceased spontaneous writhing and moved 

 only upon stimulation, but remained plump and healthy- 

 looking until the last. Does the poison of the sting act as 

 a preservative? It must have some such potency, for with- 

 out it under natural conditions these caterpillars, impris- 

 oned without food, would have died and decayed in a day 

 or two, or pupated, but it seems that after the wasps have 

 finished with them, they can do neither. 



Odynerus dorsalis Fab. [S. A. Rohwer]. 



Each species of wasp has its own highly specialized 

 method of building its nest. Some bite out the earth in 

 chunks, some dig it to pieces and carry it out in armfuls, 

 others scratch and kick it out according to various fixed 

 habits. So O. dorsaMs, too, has her own peculiar method 

 which differs from the others. She carries water, mouthful 

 by mouthful, and moistens the spot of hard, dry earth, so 

 converting it into mud which she carries out in pellets. We 

 have never chanced to see her working, except when the 

 earth was dry and hard; we should like much to know 

 whether she continues to carry water when she digs her 

 nest after a rain. Perhaps their method of work may well 

 be gleaned from the detailed description of the behavior of 

 a single individual which seemed to us typical in practi- 

 cally all points. 



