194 THE CANADIAN ENTOMOLOGIST. 



the winters are of exceptional severity. The consequent weakening of 

 the individuals by this undue exposure may produce a stunted and debili- 

 tated race, and the effects of this debility be shown in the lack of the 

 bright yellow pigmentation so characteristic of the forms from the dry, 

 warm regions of the South. 



I am far from thinking that all has been written upon the subject of 

 the variation in Crossidius that the occasion offers, but space has its limits 

 and the material is too scanty to more than indicate in what direction we 

 may look for the explanation of some of the phenomena presented. The 

 data regarding precipitation in the different localities even cannot entirely 

 be relied upon, as I have had to apply the average taken at Flagstaff to 

 Williams, which is but few miles distant, and at very nearly the same 

 elevation. In the same way it has been necessary to take that given at 

 Prescott as approximately correct for Peach Springs and Seligman. How- 

 ever, I hope the article may attract the attention of more of our American 

 students of entomology to a fascinating branch of the science, and that we 

 may soon' see in this country a number of workers who will follow out the 

 lines of investigation suggested by our English brothers, and for the fur- 

 therance of which they have established a new magazinef especially 

 devoted to the discussion of variation and its manifold causes. Most of 

 my own work in this article has been suggested by the writings of Mr. 

 Tutt, and to his works I would refer those who care to follow up the sub- 

 ject and learn, in a reasonable compass and without the mass of irrelevant 

 matter which encumbers some other recent works dealing with the specu- 

 lative side of entomology, what new fields of investigation may be opened 

 up to those who like to know the histories of their insects as well as their 

 names. 



EXPLANATION OF PLATE. 



Figs, a toy, Crossidius pulchellus, southern forms. 



Fig. k, " longipennis, Casey. 



Fig. /, " intermedins, Ulke. 



Figs, m and //, " nitidicoliis, Casey. 



Figs, o and/, " discoidens,Sa.y. 



Figs. q to t, " pulchcllns, Lee, northern forms. 



tThe Entomologist's Record and Journal of Variation. 



