210 ENTOMOLOGY 



" So firmly have these characters become ingrained in the 

 tracheate series, and so important is this relation of the hard- 

 ening of the cuticula to the musculature and to the formation 

 of body sclerites, that even the most specialized forms show 

 this primitive system of coloration; and, although there may 

 be spots and markings which have no connection with it, still 

 the chief color areas are thus closely associated." 



Development of Color Patterns. Although the causes of 

 coloration are, for the most part, obscure, it is possible, never- 

 theless, to point out certain paths along which coloration ap- 

 pears to have developed. These paths have been determined 

 by the comparison of color patterns in kindred groups of in- 

 sects and the study of colorational variations in adults of the 

 same species. The development of coloration in the individ- 

 ual, however, has as yet received but little attention excepting 

 the excellent studies of Mayer and of Tower. Butterflies, 

 moths and beetles have naturally been preferred by most stu- 

 dents of the subject. 



The most primitive colors among moths are uniform dull 

 yellows, browns and drabs the same colors that the pupal 

 blood assumes when it is dried in the air. These simple col- 

 ors prevail on the hind wings of most moths and on the less 

 exposed parts of the wings of highly colored butterflies. The 

 hind wings of moths are, as a rule, more primitively colored 

 than the front ones because, as Scudder says, "all differen- 

 tiation in coloring has been greatly retarded by their almost 

 universal concealment by day beneath the overlapping, front 

 wings." Exceptions to this statement are found in Geomet- 

 ridse and such other moths as rest with all the wings spread. 

 " In such hind wings we find that the simplest departure from 

 uniformity consists in a deepening of the tint next the outer mar- 

 gin of the wing; next we have an intensification of the deeper 

 tint along a line parallel to the margin ; it is but a step from this 

 condition to a distinct line or band of dark color parallel to 

 the margin. Or the marginal shade may, in a similar way, 

 break up into two or more transverse and parallel submarginal 



