190 THE CANADIAN ENTOMOLOGIST. 



That the yellow ground colour of most of the species is of protective 

 value, and that the black markings aid in this object by breaking the con- 

 tinuity of outline, I think no one will contradict who has seen these insects 

 in their natural homes, whether he be a believer in any of the theories 

 advanced to account for this phenomenon or not. That the variation 

 within specific limits is also very great will not be denied by one who has 

 seen cabinet series from various parts of the country ; but the meaning . 

 of this variation and its co-relations, if such there be, with the multitudin- 

 ous incidents of food, size, habitat, altitude, temperature and moisture, 

 are not to be made out at a sitting, but will take years of thought and 

 labour to demonstrate. The few facts, for the bringing forward of which 

 the present paper was written, may none the less serve a useful purpose 

 in aiding those whose investigations are of a parallel nature to keep a 

 sort of check on their own investigations, or to find that the work of 

 others may help to bear out the conclusions arrived at in their own. 



The figures a to j of the accompanying plate represent some of the 

 forms shown by Crossidius ptdcJiellus from southern localities. It will be 

 noticed that the lightest forms, h and i, are both males, while the darkest, 

 c, d and e, are females ; the male shown at j is, however, darker than the 

 females shown at a and b, the pattern resembling more closely that of g, 

 though the males with fusiform sutural blotch, h and /, are lighter than 

 the correspondingly marked females a and b; this is true also of the male 

 with shield-shaped spot (j), and its corresponding females, c, d, e, f 

 and g. The females, among themselves, show an increase in comparative 

 size of the dark spot with decrease in actual size of the insect, as will be 

 seen by comparisons of the hair-lines indicating the length of each speci- 

 men figured. The inference to be drawn here is that the female tends to 

 the possession of increase of black markings over those of the male, and 

 that the smaller specimens are likely to be darker than the larger. 



Figures tj, r, s and t are of specimens which have been referred to 

 C. hirtipes, but which I am inclined to consider simply a small form of 

 C. pulchellus, since they do not agree with the description of the former 

 species. These are all females, and do not bear out well the conclusion 

 which would seemingly be justified by the preceding series that the small 

 specimens are darkest, since r is a lighter form than the larger s. At t is 

 shown a curiously marked specimen in which the humeral spot is pro- 

 longed backward, connecting with the sutural mark at what is, in most 

 specimens, its antero-lateral angle. This may be compared with fig. e 



