238 Journal Xew York Extomological Society. [Voi. xix. 



A CONTRIBUTION TOWARD THE LIFE HISTORY 

 OF EMPHOR BOMBIFORMIS CRESS. 



By John A. Grossbeck, 

 American Museum of Natural History, New York City. 



(With Plate VII.) 



Emphor bombifoniiis Cress.^ is one of the larger digger bees and 

 is allied to the species of the genus Melissodes. It is not ordinarily 

 regarded as common ; but is not rare at Arlington, New Jersey, where, 

 in the vicinity of its nesting region, one or two hundred specimens 

 could easily be taken in the course of a day at the proper season. The 

 writer first met with the species in 1909 when several colonies were 

 found at the edge of a cat-tail marsh. In 1910 other colonies were 

 discovered in the same general region. The species seems to prefer 

 hard, shaly soil in which to nest though small colonies occur in sandier 

 soil. 



On August 30, 1909, one large colony, comprising perhaps seventy 

 bees, was discovered, which had made one hundred and twenty-seven 

 holes on an area three feet in diameter. Two smaller colonies, one 

 seventy feet and the other twelve feet away from this large one. 

 consisted of about eight and twelve individuals respectively, and a 

 still smaller number of bees constituted a fourth colony between the 

 nearest of these two larger colonies and the very large one. 



When first the bees were approached there was great commotion 

 among them ; they flew wildly about and buzzed loudly and were so 

 reluctant to enter their burrows that soon the dozen or so at first 

 present was increased to a swarm of about thirty. Quiet ensued in 

 about five minutes. Later in the day my presence was not in the 

 least disturbing to their peace, though usually I remained two feet 

 or more away from the nesting region so as not to interfere with 

 their natural behavior. 



Until well into the noon hour their actions were quite inexplicable. 

 Some were constantly leaving the nests and some were returning, 

 the former always empty-handed. Usually on returning they would 

 ' Determination made by Henry L. Viereck, Washington, D. C. 



