NATURE'S CRAFTSMEN 



structs her cylindrical nest, four-fifths of an inch long, 

 from the white down that covers a local gall or the 

 brown, hairlike tufts on certain composite flowers. The 

 cells are thus white or brown, varying with the bee's 

 gleaning, and they are placed end to end in the aban- 

 doned burrows of mason bees with which the bank is 

 honeycombed. Commonly there are two to four cells 

 in a burrow. 



Cresson's Texan Anthridium (A. Texanum), as de- 

 scribed by Mr. Melander,^ is one of our American "Resi- 

 niers " species that bind their nests together with the aid 

 of the resin of various conifers. Texanum's nest was 

 fastened to a branch of cedar about eight feet from the 

 ground. It was a small, rounded conglomerate averag- 

 ing about four-fifths of an inch in diameter, composed 

 of minute limestone pebbles, cemented together with 

 an amber - colored resin presumably taken from the 

 cedars. In this mass were six cyhndrical pupal cells, 

 wrought of a tough, brownish, translucent membrane, 

 showing the pupae within. The first two bees emerged 

 May 16th, and immediately crawled back into their 

 cases head-first. The next transformed on the 19th, 

 the fourth and fifth on the 25th, and the last, a male, 

 on June 4th, Each imago followed its leader by crawl- 

 ing back head-first into its empty pupa-case. In getting 

 out they appear to have eaten the flat end of their 

 envelope. 



The habit of wild bees to prepare cartridge-shaped 

 cells in which to rear their young runs through many 

 species. Vast numbers of solitary bees, as we have 

 seen, burrow in the ground, and therein prepare and 



* Contributions from the Zoological Laboratory of the University 

 of Texas, No. 12. 



172 



