382 LEPIDOPTERA 



necessarily became much modified with the advance of exact 

 knowledge. It is certain that the position assumed by the same 

 individual varies much according to age, and to the interval 

 since the last moult ; sometimes the attitude is much more remark- 

 able than that shown in Figure 190, A, for the anterior seg- 

 ments are held erect, as well as contracted, the front part 

 of the body being curled, and the Insect supported by the 

 claspers and two pairs only of the abdominal feet. There is, 

 too, a considerable difference in colour before and after an 

 ecdysis. Piepers, who has had a long experience among Sphingid 

 larvae in Java, considers that much of what has been written as 

 to the protective value of their colours and attitudes, is mere 

 fancy, and wild generalisation. 1 



Sphingidae have been recorded as capable of producing sounds 

 in the larval and pupal, as well as in the perfect, instars ; but 

 the method in which this is done has not been ascertained, 

 except in the case of the imago of the Death's-head moth, 

 which is well known to emit a very audible cry when not on the 

 wing; in this case it is highly probable that the method is the 

 friction of the palpi against the proboscis, as stated by Reaumur 

 and Landois ; the inner face of the palp is said to be marked in 

 this case with fine ridges or striae. 



Fam. 10. Cocytiidae. A single genus constitutes this family, 

 and there are only three or four species known ; they come from 



FIG. 191. Cocytia durvillii. New Guinea. (After Boisduval.) 



the region of New Guinea, whence the first was brought by 



D'Urville nearly a hundred years ago. They are still amongst 



1 Tijdschr. Ent. xl. 1897, pp. 27-103, 4 plates. 



