Some Hypermetamorphic Beetles 29 



Part III 



EPINOMIA 



Epinomia triangulifera Vachal is a large black bee, recorded 

 only from New Mexico, western Kansas, and Lincoln, Neb. As 

 already stated in the preceding text, it lives colonially on the salt 

 basins of Lincoln. Ten large communities 1 of these bees are 

 known to the author, all within one square mile. 



The region is alkaline, but is generally covered with man}- wild 

 flowers and grasses. Three railways traverse this area, one of 

 them having two branches. Oak creek and Salt creek approach 

 each other quite closely, and between them are at least seven or 

 eight ponds filled by the spring overflows of the two creeks. 

 The ponds are really due to excavations made in building the 

 railroad embankments. The country being low and subject to 

 many overflows, the railroads have found it necessary to raise 

 their tracks about ten feet. Where these excavations have been 

 made are found the bee colonies. Plants are absent, the ground 

 is hard, not under cultivation, and only occasionally bothered by 

 sheep or cattle grazing from the packing houses. Each com- 

 munity is bounded by an elevation of ground about a foot or so 

 high in which are the nests of numerous insects. 



Although the author's work hitherto at these colonies has been 

 of secondary importance, it will henceforth be taken up as thor- 

 oughly as possible. For several years one or two of these col- 

 onies have been known, and during the past summer several 

 others have been found. A study of a single colony will suffice 

 to explain the conditions. As already stated, the only adverse 

 conditions are those brought about by nature. These conditions, 

 however, are very numerous and will appear throughout the 

 discussion. 



The first community studied was several hundred feet long 

 and not more than ten feet wide, on an elevation of a foot or so 



1 The term community is here applied to such gatherings, as exhibited by 

 Epinomia, in which in a certain limited region are myriads of individual 

 homes, possessed often by very different species. Usually some species pre- 

 dominates and that species gives the name to the community. Several colo- 

 nial societies might exist in the midst of a community. 



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