1896.] 



ENTOMOLOGICAL NEWS. 



217 



J 



It prefers as a nesting site the broken twigs of the elder tree 

 or fennel plant, burrowing from the end in the medium sized 

 branches. The burrow when completed seldom extends more 

 than six or seven inches into the branch, 

 ^ ^.-«£, and is usually four lines wide. In the 



typical nest the cells as shown in the illus- 

 tration are crowded together at the bot- 

 tom, while on the top of and usually con- 

 tiguous to the outermost cell are alternating 

 layers of pith and clay, the former evidently 

 gathered from the sides of the burrow above, 

 as that part is wider than the section oc- 

 cupied by the cells. Near the entrance to 

 the burrow the opening is further obstructed 

 by a series of clay partitions with the in- 

 tervals between filled with pith as in the 

 other. The partitions are somewhat pecu- 

 liarly constructed, both the upper and 

 lower being fashioned on the same plan. 

 The lower usually has a layer of pith next 

 the cell of a thickness varying from one- 

 half to one-eighth of an inch, on top of 

 which is a disc of clay one-half line thick, 

 then one-eighth of an inch of pith and 

 another disc, etc. The outer defence is 

 wholly constructed of alternating layers 

 of clay discs and pith differing only from 

 the deeper one in being begun and finished 

 with a clay disc. The cells measuring 6 

 by 3 lines are closely packed together at 

 the bottom of the burrow, only a thin clay 

 v') f am \v disc such as is used in the partitions, one 



line in thickness intervening between each. 

 In the specimens kept under observation 

 the bees hatched out at various dates from 

 March 15 to April 12. 



The parasites affecting them were four 



in number, the most common being Cryp- 



tus albitarsis Cress, which affected 25 per 



cent. The cocoons of Cryptus are in shape exactly similar to 



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A ■• - 



