1893-] ENTOMOLOGICAL NEWS. 151 



Leptotrachelus dorsalis Fab. is not an abundant insect, but I 

 found a spot once (late in fall), in a moist piece of woods, where 

 they were in unlimited numbers under and among wet leaves. In 

 the same region nearly a thousand specimens of Platynus basalis 

 were taken on less than an acre of ground. Here, too, Lathro- 

 bium armatum Say was abundant ; nearly every log and bit of 

 bark turned over yielded specimens. Many other species were 

 abundantly represented. 



-o- 



The Nest and Parasites of XYLOCOPA ORPIFEX,* Smith. 

 By ANSTRUTHER DAVIDSON, Los Angeles, Cal. 



In this section of Southern California four or five species of 

 Xylocopa are found. This last season, while collecting with 

 Professor Coquillett, of our National Division of Entomology, 

 we for the first time discovered the nests of X. orpifex in abund- 

 ance on Wilson's Peak, a mountain of 5000 feet altitude. At 

 the time of our visits in June and August, 1892, we collected 

 numerous specimens of the. bees and their nests. While the 

 nests do not seem to differ in many particulars from the nests of 

 X. virginica as described by Packard in his well-known guide 

 to the study of insects, yet there are numerous problems con- 

 nected therewith which I wish the readers of the NEWS would 

 throw some light upon. 



I picked up one piece of wood four inches in diameter and 

 about three feet long, and as there was but one external opening 

 it is presumable all the cells contained therein were the work of 

 one bee. From a diagonal entrance the tunnels were driven 

 longitudinally a distance of three or four inches on each side. 

 Parallel to this was another of a similar length, and a third very 

 much shorter, the cells in all numbering twenty. The tunnel is 

 not all of one uniform width, but is dilated in the centre of 

 each cell, so that the tunnel measures three-eighths of an inch 

 in diameter at the extremities, and half an inch at the centre of 

 each cell. 



The partitions are constructed in a manner apparently identical 

 with those of X. virginica, but the ribbon-like coil has five com- 

 plete whorls, and is one-eighth of an inch wide. After the par- 



* From a paper read before the S. California Science Association. 



