WASPS, SOCIAL AND SOLITARY 



watched for her, at intervals, all through that day and 

 the next, when we were forced to conclude that our 

 faithful little worker had fallen a victim to some bird 

 or beast. We did not disturb the nest until four days 

 later, when we cut the stalk, and examined it. 



We found that the tunnel was thirty-nine centimeters 

 in length. This was a long distance for her to excavate, 

 and, all things considered, her progress had been rapid. 

 We have opened a number of stems that had been stored 

 by this species, and all the excavations were from thirty 

 to forty centimeters in length, the width of the gallery 

 being about three and one half millimeters, while on each 

 side there was from one to one and one half millimeters 

 of pith that had not been cut away. Of course these 

 points varied with the diameter of the stem and also 

 with the size of the worker. 



Our little stirpicola had stored one cell, had laid an 

 egg, and had built a partition of pith across the stem as 

 a floor to the second cell, before her untimely taking off. 

 Had she lived, ten or twelve cells would have been stored, 

 one above the other. The completed cell contained a 

 larva and parts of eighteen flies of different sizes, four 

 species being represented. The flies had all been at- 

 tacked by the larva, the abdomens of some and the tho- 

 races of others having been eaten. The larva continued 



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