THE CANADIAN ENTOMOLOGIST 301 



POLLINATION OF ALFALFA BY BEES OF THE GENUS 



MEGACHILE. TABLE OF CANADIAN SPECIES 



OF THE LATIMANUS GROUP. 



BY F. W. L. SLADEN, APIARIST, DOMINION EXPERIMENTAL FARMS. 



A Study has been made of the species of bees that trip and 

 therefore, presumably, pollinate the flowers of alfalfa in the parts 

 of Canada where this plant is or can be grown for seed. 



In July and August, 1916, the females of a species of leaf- 

 cutter bee, Megachile diligens, Sladen* (latimanus Cockerell, not 

 of Say) were found to be visiting the fields of alfalfa in bloom and 

 tripping the flowers in considerable numbers at Medicine Hat and 

 Lethbridge, Alta., each flower visited being tripped. The same 

 thing was noticed in 1917, when they were observed to be tripping 

 the flowers at an average rate of 17 per minute. This species 

 was more numerous in the alfalfa fields than five other species 

 of Megachile together, (perihirta Ckll., calogaster, Ckll., vidu Sm., 

 manifesta Cr. and hrevis Qr.) all of which performed the same 

 service. Several species of bumble-bees, fairly plentiful, worked 

 more slowly and often failed to trip the flowers. Honey-bees, also 

 plentiful, visited the flowers without tripping them. 



Observations made on July 20, 1917, at Summerland. B.C., 

 and on July 21, at Keremeos, B.C., gave the same results, except 

 that perihirta was the abundant species, M. diligens not having 

 been met with in British Columbia. 



M. perihirta was found nesting gregariously in a nearl\- new 

 and bare gravel railway embankment at Cochrane, Ont., on August 

 9, 1917. A nest of the same species was found in a nearly new 

 gravel road leading to a dwelling house at Invermere, B.C., in 

 July, 1914. There is, therefore, some hope that perihirta might be 

 encouraged to breed in the vicinity of alfalfa fields by spreading 

 gravel and making it firm by rolling. Diligens might also be en- 

 couraged in this way because it is very closely related to perihirta 

 and probably has similar nesting habits. 



Closely related to these two species is a third, latimanus Say. 

 found in Southeastern Canada. These three species constitute 



*The name diligens was first used in the Agricultural Gazette of Canada, 

 Feb. 1918, p. 125. 



September, 1918 



