THE WOOD-BORERS. 79' 



of the last one taken in; the second cell was provisioned with ten 

 spiders with the egg on the seventh, so that three had been 

 brought in after it was laid; the third cell had the egg on the 

 last spider, as did also the fourth. All of these eggs hatched 

 on the twenty-ninth, the two outer ones, that were laid last, be- 

 tween eight and nine o'clock in the morning and the two that 

 were laid earlier between two and three in the afternoon. This 

 was the biggest day's work that we have ever recorded for any 

 of our hunting wasps. 



With both species {T. ruh'ociiwtum and T. alhopilosum), 

 when the preliminary Avork of clearing the nest and erecting 

 the inner partition hasi been performed by the female, the male 

 takes up his station inside the cell, facing outward, his little head 

 just filling the opening. Here he stands on guard for the greater 

 part of the time until the nest is provisioned and sealed up,, 

 occasionally varying the monotony of his task by a short flight. 

 As a usual thing all the work is performed by the female, who 

 applies herself to her duties with greater or with less industry 

 according to her indi^adual character; but the male doubtless 

 discharges an important office iui protecting the nest from para- 

 sites. We have frequently seen him drive away the brilliant 

 green Chrysis fly which is always waiting about for a chance to^ 

 enter an unguarded nest. On these occasions the defense is car- 

 ried on with great vigor, the fly being pursued for some distance 

 into the air. There are usually two or three unmated males fly- 

 ing about in the neighborhood of the nests, poking their heads 

 into unused holes, and occasionally trying to enter one that is 

 occupied, but never so far as we have seen, with any succees, 

 the male in charge being always quite ready and able to take 

 care of his rights. The males, however, made no objection 

 when strange females entered the nest as they sometimes did by 

 mistake, nor did the females object to the entrance of a strange 

 male when the one belonging to the nest happened to be away, 

 but in such cases the rightful owner, on his return, quickly 

 ejected the intruder. We often amused ourselves, while we were' 

 watching the nests, by approaching the little male, ai» he stood 



