214 THE ORIGIN AND DEVELOPMENT 



the tint next the outer margin 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 mar- 

 ginal shade may, in a similar way, break up into 

 two or more transverse and parallel submarginal 

 lines, a very common style of ornamentation, 

 especially in moths. Or, again, starting with the 

 marginal shade, this may send shoots or tongues 

 of dark color a short distance toward the base, 

 giving a serrate inner border to the marginal 

 shade ; when now this breaks up into one, two, or 

 more lines or narrow stripes, these stripes become 

 zigzag, or the inner ones may be zigzag, while 

 the outer are plain a very common phenom- 

 enon. 



A basis such as this is sufficient to account for 

 all the modifications of simple transverse mark- 

 ings which adorn the wings of Lepidoptera, and 

 explains why, amid all the profound modifica- 

 tions the color patterns have undergone, the trans- 

 verse style of markings holds a fundamental posi- 

 tion ; and why such markings are far more prev- 

 alent on the outer than on the basal half of the 

 wing, and are also so frequently scalloped. All 

 the steps of this process, as I have explained it, 

 apply equally well to the front wing, excepting 

 that we cannot there so well trace the initial step 



