THE CANADIAN ENTOMOLOGIST. 107 



REMARKS ON THE DISTRIBUTION OF HETEROPTERA. 



BY J. R. DE LA TORRE BUENO, WHITE PLAINS, N. Y. 



•Among the many problems of nature that engage the atten- 

 tion of the biologist there is one that to me has always been of the 

 utmost interest. It is that of the occurrence of the same species 

 in widely separated regions or through extensive and seemingly 

 dissimilar areas or in isolated and restricted habitats. The classic 

 example of the last, familiar to all entomologists, is the peculiar 

 subarctic and alpine butterfly Oeneis or Chionohas semidea which 

 from the wilds of Labrador jumps to the high peaks of the 

 Presidential Range of the White Mountains and again is not 

 found till we come to the Rockies in Colorado. Here, however, 

 we have a tenable explanation for this great and peculiar range, 

 in the fact that this is an arctic genus which spread during the 

 ice-age throughout its vast territory, and which, with the recession 

 polewards of the ice cap and the frigid temperatures it caused, 

 travelled northward in its wake. Some, however, followed the 

 receding line of perpetual snow up the mountain sides, and where 

 these were of sufficient altitude, they have contrived to maintain 

 themselves to this late date in the geological history of the earth. 

 In this paper the Hemiptera only are to be considered, 

 more especially the Heteropterous forms supposed to be common 

 to America and Europe. At the outset we are confronted with 

 a difficulty, which arises from the mistaken reference of American 

 species to European forms. This troublesome condition is 

 directly due to the meagre descriptions of the older authors, who 

 availed themselves principally of colour for specific distinctions 

 and put the structural differences in the generic characterizations. 

 In part, however, our native entomologists are at fault, since 

 much of this confusion can be traced to their neglect of the 

 study of the cognate European species, which, even though they 

 are of the same colour patterns as ours, in so far as any written 

 description can go, are nevertheless sufficiently difiterent in form 

 and structure to be readily distinguishable by the trained eye. 

 This condition in the Hemiptera is being rapidly adjusted, due 

 almost entirely to the labours of the Europeans. In fact, our own 

 present lack of sufficient acquaintance with their writings leads 

 some of us to the perpetuation of errors long since dispelled. It 



April, 1913 



