1918] Life History of Bombus Auricomus 47 



bumble-bee workers, I found the puparia of Zodion oblique- 

 fasciatum Macq. (Malloch det.). The nest was also infested 

 by the phycitid moth, Vitulas edmansii Pack., which has been 

 previously reported from the nest of Bombus perplexus Cress, 

 by Franklin ('13). 



B. LATER HISTORY OF THE COLONY. 



After the removal of the nest to an observation box, one 

 or more males emerged almost every day for two weeks, but 

 no additional queens or workers. The males would stay in the 

 nest for several days and then leave, perhaps returning and 

 perhaps not. An attempt was made to secure the fertilization 

 of the three queens by confining them with the males, but this 

 failed. On October 9, two workers were still alive in the nest, 

 but could scarcely move about. On October 12, these two 

 workers succumbed to the increasing cold nights and the colony 

 came to an end. 



IV. Summary of the Life History. 



The following summary of the important facts in the life 

 history of Bombus auricomus is based upon a study of the two 

 colonies in this paper, and also upon my previous account 

 ('17). 



1. The nests are usually established in this vicinity sometime 

 between the middle of May and the middle of June. 



2. The bumblebees of this species are of a docile disposition as 

 compared with such a species as Bombus pennsylvanicus De Geer. 



3. The colonies are of rather small size. 



4. The workers sometimes lay eggs, which are capable of hatching. 



5. The eggs are laid in separate cells, several of which may be 

 adjoining, but the cell-individuality is never lost. 



6. The larvas continue to remain isolated from other individuals 

 in the same stage of development. 



7. The life-cycle varies in individual cases, but may be said to 

 last for all sexes about three and one-half weeks. 



BIBLIOGRAPHY. 



1»13. Franklin, H. J. The Bombidae of the New World. Trans. Amcr. Ent. Soc, 



Vol. 38, pp. 177-486; Vol. 39, pp. 73-200; pi. 1-22. 

 1917. Prison, T. H. Notes on Bombidae, and on the Life History of Bombus 



auricomus Robt. Ann. Ent. Soc. Amer., Vol. 10, pp. 277-286, pis. 23-24. 

 1912. Sladen, F. W. L. The Humblebee. 283 pp., 34 figs. London; Macmillan Co. 



