June, igoi.] Smith : On Some Digger Bees. 69 



13th, though some were completed in the cells. This gives a full 

 month for the pupal stage. 



July 14th, Mr. Brakeley's notes are resumed, and as the result of 

 his observations, he thinks temperature and relative maturity of the 

 bee determine the size of the cell clusters and the number of eggs 

 laid. Early in the season when ova are developing slowly, the bee 

 makes only a single cell cluster, because she feels there will be plenty 

 of time to build another series before she needs them : that series will 

 contain from four to eight cells and form the bulk of the deposit. 

 Late bees, coming out in hot weather, feel the ova developing too 

 rapidly to allow of much delay and they build as many cells in one 

 cluster as there may be need for. In case, after the main clusters are 

 provided for, there be some late ovarian developments, a small clus- 

 ter, lower down than usual is provided, 



July 15th, bees were seen on the wing, and in the field where the 

 adult was taken out of the cell July 13th, new diggers are already be- 

 ginning to be notable. Whether males ever go down into these new 

 burrows was not observed. On the 17th there were many new sand 

 heaps, and on the 21st there was a general hatching and a general 

 going down. Mr. Brakeley, in the course of some notes, writes : 

 " About this time, happened to glance over the bee-bed and saw 100 

 blue bees or more, hovering low to the ground. Can't say where 

 they come from, but I suspect that while I was working the upper 

 clusters the lower series were unloading their adult bees." A sample 

 of the conditions is shown in the following : 



Case I : Top cluster, 2 cells : i bee out, i cell yet closed, bee 

 ready to emerge. Case 2 ; same status. 



Case 3: Top, 2 cell cluster bees out of both; but i captured; 

 lower cell cluster with larvae. 



Case 4 : Top cluster, 2 bees out ; lower, i bee out, one mature 

 and ready to come out. 



Case 5: 4 cell clusters: ist of 10 cells, several empty, others 

 with mature bees ; 2d of 6 cells, some empty, others with bees nearly 

 mature ; 3d or 4 cells all with pupse ; 4th of one cell with larva. 



July 2 2d, the last observation was made, and it was concluded 

 from the fact, that digging began just as it did in May, that there 

 would be another brood ready September 15th to 30th. So on Sep- 

 tember 17th Mr. Brakeley and myself were again on hand, making 

 an observation trip through the blue bee territory. We saw no signs 



