MAYER: COLOR AXD COLOR-PATTERNS. 183 



Eno-lancl, called attention to the following facts : the transverse 

 series of dark spots so often seen in the body of the wings of 

 Lepidoptera are invariably placed in the interspaces between the 

 longitudinal veins, never upon the veins themselves, excepting 

 onlv in rare instances, where the spots occur at the extreme margin. 

 He also pointed out that in many types of moths all differentiation 

 in coloring has been greatly retarded, so far as the hind wings are 

 concerned, by their almost universal concealment by day beneath 

 the overlapping front wings. In these cases " the simplest departure 

 from uniformity consists of a deejjening of the tint next the outer 

 margin of the wing." It is but a step from this condition to a 

 band of dark color or a row of spots parallel with the margin. This 

 explains Avhy the transverse st^'le of markings, for the hind wings 

 at least, is so common. Scudder showed that "the number of 

 instances, in butterflies, in which similar markings appear in the 

 same areas of the two wings, and in the same relative position 

 in these areas, is far too common to be a mere coincidence. It is 

 most readily traced in the disposition of the ocelli, which are very 

 apt to be similar in size and perfection, and to be situated between 

 the same branches of homologous veins." 



(2) Laws of Color-Patterns. As a result of my own study of 

 the wings of moths and butterflies, I am prepared to propose the 

 following additional laws of color-patterns. («) Any spot found 

 upon the wings of a moth or biitterfly tends to be bilaterally symmet- 

 rical both as regards form and color., the axis of sj^mmetry being 

 a line passing through the center of the interspace in which the 

 spot is found, and parallel to the direction of the longitudinal 

 nervures. For example, in Figs. 6 and 7, Plate 2, each spot is 

 bilaterally symmetrical about the axis HH. The same law holds 

 for the spots represented in Figs. 8-1-4 and 16. 



{h) Spots tend to appear not in one interspace only., but as a row 

 occupying homologous places in successive interspaces. Indeed we 

 almost always find similar spots arranged in linear series, each sim- 

 ilar in shape and color to the others and occupying the center of its 

 interspace. The rows of spots represented in Figs. 8-14 and 10 

 will suftice to illustrate this law. 



It is interesting to notice that bands of color are often made by 

 the fusion of a row of adjacent spots ; and, conversely, chains of 

 spots are often formed by the breaking up of bands, leaving 

 a row of spots occupying the interspaces. Many instances of this 



