312 THE DESCENT OF MAN. 



I hear from Mr. Stainton, do not habitually expose the under 

 surface of their wings to full view, we find this side very rarely 

 colored with a brightness greater than, or even equal to, that 

 of the upper side. Some exceptions to the rule, either real or 

 apparent, must be noticed, as the case of Hypopyra." Mr. Trimen 

 informs me that in Guenge's great work, three moths are figured, 

 in which the under surface is much the more brilliant. For 

 instance, in the Australian Gastrophora the upper surface of the 

 fore-wing is pale grayish-ochreous, while the lower surface is 

 magnificently ornamented by an ocellus of cobalt-blue, placed 

 in the midst of a black mark, surrounded by orange-yellow, and 

 this by bluish-white. But the habits of these three moths are 

 unknown; so that no explanation can be given of their unusual 

 style of coloring. Mr. Trimen also informs me that the lower 

 surface of the wings in certain other Geometree" and quadrifld 

 Noctuse are either more variegated or more brightly-colored than 

 the upper surface; but siome of these species have the habit of 

 "holding their wings quite erect over their backs, retaining them 

 "in this position for a considerable time," and thus exposing the 

 under surface to view. Other species, when settled on the ground 

 or herbage, now and then suddenly and slightly lift up their 

 wings. Hence the lower surface of the wings being brighter 

 than the upper surface in certain moths is not so anomalous as it 

 at first appears. The Saturniidae include some of the most beau- 

 tiful of all moths, their wings being decorated, as in our British 

 Emperor moth, with fine ocelli; and Mr. T. W. Wood^' observes 

 that they resemble butterfiies in some of their movements; "for 

 "instance, in the gentle waving up and down of the wings as if 

 "for display, which is more characteristic of diurnal than of 

 "nocturnal Lepidoptera." 



It is a singular fact that no British moths which are brilliantly 

 colored, and, as far as I can discover, hardly any foreign species, 

 differ much in color according to sex; though this is the case with 

 many brilliant butterfiies. The male, however, of one American 

 moth, the Saturnia lo, is described as having its fore-wings deep 

 yellow, curiously marked with purplish-red spoT;s; whilst the 

 wings of the female are purple-brown, marked with gray lines." 

 The British moths which differ sexually in color are all brown. 

 or of various dull yellow tints, or nearly white. In several 

 species the males are much darker than the females,™ and these 



i« See Mr. WormaW on this moth: 'Proc. Ent. Soc' March 2na, 1868. 



1' See also an account of the S. American genus Erateina (one of the 

 Geometrae) in 'Transact. Ent. Soc' new series, vol. v. pi. xv. and xvi. 



" 'Proc. Ent. Soc. of London,' July (j, 1868, p. xxvii. 



"Harris, 'Treatise,' &c., edited by Flait, 1862, p. 395. 



^ For instance, I observe in my son's cabinet that the males are 

 darker than tlie females in the Lasiocampa quercus, Odonestis pota- 



