Chap. XL] BUTTERFLIES AND MOTHS. 385 



But the habits of these three moths are unknoAvn ; so that 

 no explanation can be given of theii* unusual style of col- 

 oring. Mr. Trimeu also informs me that the lower sur- 

 face of the wings in certain other Geometrae " and quadri- 

 fid Noctuse is either more variegated or more brightly- 

 colored than the xipper surface ; but some of these species 

 have the habit of " holding their wings quite erect over 

 their backs, retaining them in this position for a consider- 

 able time," and thus exposing to view the under surface. 

 Other species, when settled on the ground or herbage, 

 have the habit of now and then suddenly and slightly 

 lifting up their wings. Hence, the lower surface of the 

 Avings being more brightly colored than the upper surface, 

 in certain moths, is not so anomalous a circumstance as it 

 at first appears. The Saturniidse include some of the 

 most beautiful of all moths, their wings being decorated, 

 as in our British Emperor moth, with fine ocelli ; and Mr. 

 T. W. Yfood " observes that they resemble butterflies 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 Lepi- 

 doptera." 



It is a singular fact that no British moths, nor, as far 

 as I can discover, hardly any foreign species, which are 

 brilliantly colored, differ much in color according to sex ; 

 though this is the case with many brilliant butterflies. 

 The male, however, of one American moth, the Saturnia 

 lo, is described as having its fore-wings deep yellow, 

 curiously marked with purplish-red spots ; while the wings 

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

 The British moths which differ sexually in color are all 



'3 See also an account of the South American genus Erateina (one of 

 the Geometrae) in ' Transact. Ent. Soc' new series, vol. v, pis. xv., xvi. 

 1* ' Proc. Ent. Soc. of London,' July 6, 1868, p. xxvii. 

 15 Harri:-, ' Treatise,' etc., edited by Flint, 18G2, p. 395. 



