1921] Wheeler: Some Social Beetles 73 



interest. He finds that during starvation, the loss of water in 

 these insects is always greater than that in body weight or in 

 the solids. "This shows that starvation in the grasshopper 

 results in a rapid loss in water which has a decidedly quick and 

 fatal effect." 



I have been unable to ascertain the length of the larval per- 

 iod or the number of lai-val moults of Coccidotrophus. As no 

 exuviae were found in the petioles it would seem that they 

 must be devoured either by the beetles or by the larvae them- 

 selves. The food of the larvae, as we have seen, consists of the 

 amber-colored nutritive parenchyma and of the sweet excreta of 

 the coccids, the former evidently supplying the proteids, the 

 latter the sugar and most of the water. So concentrated a diet 

 should be very favorable for growth and probably the whole lar- 

 val period at tropical temperatures occupies only two or three 

 weeks. The fat-body, however, does not seem to become very 

 voluminous till the last larval instar when the segments of 

 the body become more convex and puffed out with the accumula- 

 tions of adipocytes. Yet this condition, which immediately pre- 

 cedes pupation, does not tend greatly to inhibit the activities of 

 the larva. 



When a petiole containing a colony in what I have called the 

 third stage is opened, one or more cocoons are invariably found 

 in the cavity (Plate V). They are oblong-elliptical structures, 

 5-6 mm. long and 2-3 mm. broad and seem to consist of the 

 same chocolate brown substance as the frass-ridges. Their 

 walls are of uneven thickness, with smooth inner and rough- 

 ened outer surfaces, and are easily fractured. These cocoons 

 do not lie loosely in the cavity but are attached to some flattened 

 surface of the wall where the lumen of the petiole is rather 

 broad, i.e., away from the pointed ends, and always have their 

 long axes parallel with the long axis of the cavity. They are 

 sometimes single but more frequently occur in pairs or in 

 groups of three or four. When in pairs, the two cocoons lie 

 abreast of each other, when in threes or fours, the third and 

 fourth cocoon are often built on top of a basal pair. Such groups 

 of cocoons are so voluminous that they obstruct the lumen of 

 the petiole and leave only a narrow passage for the beetles to 

 move between the more roomy spaces at either end of them. 



