THE CANADIAN ENTOMOLOGIST 129 



JMedicine Hat, too, a general change in tegmental colour, which must not be 

 confounded with hair colour, is noticeable. Yellow bands and markings in the 

 bare or nearly bare bees and wasps expand and multiply at the expense of black, 

 and species, often of giant size, having red markings, especially on the first 

 segment of the abdomen begin to appear, notably in the bee genera Anthidiiim, 

 Epeoiiis and Nomada, and in the wasp genera, Vespa, Bembix, Microhemhex, 

 (yellow); Phi Ian thus, Cerceris and Odyneriis (red markings). Several species 

 of Andrena from Toronto and Winnipeg regions have a red abdomen, but on 

 the coasts and in the North the abdomen is always black. At Oxford, England, 

 Andrena hattorfiana has a red abdomen, but at Dover the abdomen of this species 

 is black. 



Reduction of humidity acts in the same way as heat, but it appears to 

 be less important. Indeed, in the present study, it can be demonstrated to be 

 a negligible factor if rainfall be taken as its criterion. The summer rainfall 

 of Dover and Victoria, B. C, is much less than that of Ottawa and Toronto. 

 But humidity cannot be judged by rainfall which increases the relative humidity 

 of soil and air in our region much less than heat reduces it. 



Differences in winter temperature and rainfall, however, do not affect the 

 characters to any extent. The same varieties are found on the mild and wet 

 Pacific Coast as on the dry cold mountains. This is the more remarkable when 

 when we remember that the distribution of the plants on which the bees feed 

 is greatly affected by winter climate. 



The same differences that are found between bees in a cool coastal summer 

 climate and a warm interior one, are found between spring and summer flying 

 bees in the same climate, and they are more marked in regions like Britain and 

 the Pacific Coast where the spring is cool, than the interior of Canada where it 

 warms up quickly. In England, and to a less extent in Ontario, the one species 

 of Colletes that flies in the spring is larger and has a longer coat with feebler 

 felt bands than the many species that fly in summer. Similarly, the early 

 spring flying species of Andrena are large, have long coats and no felt bands; 

 the summer flying species are generally smaller (except giant southern forms), 

 have shorter coats with bare areas and frequently felt bands. At Ottawa, 

 A. cockerelli which appears in spring before the snow has gone, has a longer, 

 shaggier coat with less tendency to bare areas than any other species in Eastern 

 Canada. Britain and the Pacific Coast have several large, robust, shagg>' 

 and long haired species of Anthophora appearing in early spring as well as shorter 

 haired summer species, but the long haired spring species are not found on the 

 prairie or in Eastern Canada. 



Many of the differences noted are more shown in the females than in the 

 males. Abdominal felt bands are always better developed in the females than 

 in the males. Females of numerous species develop red tegumental markings, 

 while the males remain black or yellow. In many species of Sphecodes the abdo- 

 men is black in the male and red in the female. In a large wasp found in Medicine 

 Hat, Alta., Eucerceris gloriosa, the male is yellow and the female red. In Vespa 

 Carolina, a species found at Point Pelee, Ont., by Mr. Taverner, the queen has 

 orange markings, while in the workers these markings are yellow. Can the 

 reason be that the female has a longer adult existence, or that the continuance of 

 the species depends solely upon it after the male has died? 



