320 SILK-MOTHS. Chap. VIIL 



received a similar statement from the eminent naturalist, M. fie 

 Quatrefages. Caj:>tain Hntton also says 76 that the moths of all 

 kinds vary mnch in colour, but in nearly the same inconstant 

 manner. Considering how much the cocoons in the several races 

 differ, this fact is of interest, and may probably be accounted for 

 on the same principle as the fluctuating variability of colour in the 

 caterpillar, namely, that there has been no motive for selecting and 

 perpetuating any particular variation. 



The males of the wild Bombycidse " fly swiftly in the day-time 

 and evening, but the females are usually very sluggish and 

 inactive." 77 In several moths of this family the females have 

 abortive wings, but no instance is known of the males being 

 incapable of flight, for in this case the species could hardly have 

 been perpetuated. In the silk-moth both sexes have imperfect, 

 crumpled wings, and are incapable of flight ; but still there is a 

 trace of the characteristic difference in the two sexes ; for though, 

 on comparing a number of males and females, I could detect no 

 difference in the development of their wings, yet I was assured by 

 Mrs. Whitby that the males of the moths bred by her used their 

 wings more than the females, and could flutter downwards, though 

 never upwards. She also states that, hen the females first 

 emerge from the cocoon, their wings are less expanded than those 

 of the male. The degree of imperfection, however, in the wings 

 varies much in different races and under different circumstances. 

 M. Quatrefages 78 says that he has seen a number of moths with 

 their wings reduced to a third, fourth, or tenth part of their normal 

 dimensions, and even to mere short straight stumps : " il me semble 

 qu'il y a la un veritable arret de developpement partiel." On the 

 other hand, he describes the female moths of the Andre Jean breed 

 as having " leurs ailes larges et etalees. Un seul presente quelques 

 courbures irregulieres et des plis anormaux." As moths and butter- 

 flies of all kinds reared from wild caterpillars under confinement 

 often have crippled wings, the same cause, whatever it may be, has 

 probably acted on silk-moths, but the disuse of their wings during 

 so many generations has, it may be suspected, likewise come into 

 play. 



The moths of many breeds fail to glue their eggs to the surface 

 on which they are laid, 79 but this proceeds, according to Capt. 

 Hutton, 80 merely from the glands of the ovipositor being weakened. 



As with other long- domesticated animals, the instincts of the 

 silk-moth have suffered. The caterpillars, when placed on a mul- 

 berry-tree, often commit the strange mistake of devouring the 

 base of the leaf on which they are feeding, and consequently fall 



76 ' Transact. Ent. Soc.,' ut supra, 78 ' Etudes sur les Maladies du Ver 

 p. 317. a Soie,' 1859, pp. 304, 209. 



77 Stephen's Illustrations, ' Haus- 79 Quatrefages, ' Etudes,' &c, p. 

 tellata,' vol. ii. p. 35. See also Capt. 214. 



Hutton, 'Transact. Ent. Soc' ibid,, 80 'Transact. Ent. Soc.,' ut supra, 



p. 152. p. 151. 



