June, igoi.i Smith : On Some Digger Bees. 53 



arrangement of laterals from what had been noted in Colletes, and be- 

 low the end of the cast, 41 inches from the surface, the hole yet went 

 down : in other words the plaster had set before it reached the bottom. 

 Other casts ran down 473/^ and 50^0 inches, respectively, and at the 

 bottom of the holes bees were found. 



April 19th it rained, but on the 20th digging was renewed and one 

 burrow was followed down 58 inches. Two bees were found in the 

 bottom of one of these holes. Additional casts were made and were 

 dug out from time to time, until well along in May, and at this time 

 no two casts were alike. There was always the deep vertical extend- 

 ing down from forty-five to sixty inches. Beginning about six or 

 eight inches from the top, lateral burrows might be expected, running 

 at right angles an inch or two and then broadening out into a circular 

 chamber about three-sixteenth inch in height, variable in diameter. 

 From this chamber a variable number of verticals extended down a 

 variable distance — sometimes only half an inch, more generally an 

 inch, and almost always one or two were much deeper. Occasionally 

 one of these verticals was extended down several inches, and it might 

 even run off diagonally ; though this was rare. So we found a few 

 cases where the circular chamber was omitted and there was an irregu- 

 lar branching off from the lateral. There seemed neither rhyme nor 

 reason in the differences and we were totally unable to find any traces 

 of bees having developed anywhere in the burrows or the cells con- 

 nected with them. So the number of laterals and cell clusters varied. 

 Usually there were two ; not infrequently there were three and rarely 

 there was a fourth. Below 18 inches we never expected to find cell 

 clusters ; but sometimes there were irregular chambers forming little 

 fingers in the casts, which might be found at almost any depth. The 

 longest burrow measured extended 64 inches down ; through a layer 

 of sand, through a soft yellow clay into a stratum of hard red clay in- 

 termixed with iron, through this clay and through an eight-inch layer 

 of sea sand it went through clay and hard gravel to water-bearing sand 

 beneath. In one case eight bees were found piled one above the other 

 nearly five feet under ground. When brought to the surface they 

 were torpid and did not resent handling ; but they became active very 

 c[uickly in the bright sunlight and started flight when allowed to do so. 



Of one thing we were of course certain : all these burrows had 

 been made in 1897 ; but why were so many bees in one home, and 

 why was there no trace of breeding? All the specimens were females. 



