398 THE CANADIAN ENTOMOLOGIS'T. 



remaining eleven regions, of which seven — one of the seven being the 

 Indian region — contain no endemic representatives of the family, it is 

 3.8 less than for the per cent, of all forms endemic. In all regions except 

 the Antarctic some genera of the Apidae are found, and are, indeed, 

 distributed among the several regions with considerable uniformity. 

 Tropical South America has 46.7 per cent., while the next largest number 

 is that for the Mediterranean region, with 37.2 per cent., and the Northern 

 region with 36.4 per cent. The average for the tropical and extra-tropical 

 South American and Australian regions is 53.3 per cent., while for the 

 other regions it is 19 per cent. The per cent, of all Apidae occurring in 

 4, 6 and 7 exceeds the per cent, of all Hymenoptera in these regions by 

 17.4, while in the remaining eleven regions the per cent, of Apidae 

 occurring exceeds that for the total number of Hymenoptera by only 4.4. 



As is well known to entomologists, the Hymenoptera are but little 

 exploited systematically, and conclusions concerning their distribution 

 must be only tentative. It is obvious from these tables that the data 

 available upon the Hymenoptera are inadequate and unsatisfactory, and it 

 will be many years before this vast group is sufficiently known systematic- 

 ally to justify any but tentative conclusions. Such data as we have, 

 however, seem to point quite clearly to a great relative differentiation of 

 the Apid£e in the regions in which our much more complete knowledge of 

 the geographical distribution of plants has shown the apically dehiscent 

 genera of the three types apparently adapted to pollination by the Apid« 

 to be most abundantly represented, and in view of the entire mass of 

 evidence, it is difficult to refrain from the conclusion that there is a direct 

 reciprocal relation between the distribution of the two classes of organisms. 

 The evidence is at least so strong as to demand the co-operation of 

 entomologists and botanists in the collection of data, which promises a 

 better insight into some of the problems of taxonomy, biogeography and 

 evolution. 



One of the things which is most needed at the present time is a fuller 

 knowledge of the insect visitors concerned in the pollination of flowers, 

 especially of the flora of tropical regions, and while in many cases only the 

 most careful investigations by one especially trained in floral ecology will 

 yield satisfactory conclusions as to the stage of adaptation of a given 

 species, it is also true that lists of visitors with some indication of their 

 actions in visiting flowers such as can be easily prepared, and in many 

 cases have been prepared, by the entomologist in his field studies, will 

 enhance very greaily the value of his own publications, and will contribute 

 much towards the data for larger problems. 



