SPHINGIDES. 369 



xl., pp. 27 — 103) from a study of the Javan Sphingid larvae that 

 much of what has been written as to the protective value of their 

 colours and attitudes is fanciful and not warranted by facts. Kirby 

 and Spence state that " the larva of Manduca ( Acherontia) atropos 

 if disturbed, draws back rapidly, making at the same time a rather 

 loud noise which has been compared with the crack of an electric 

 spark." Reed describes {Can. Ent., i., p. 40) a Canadian Amorphine 

 larva which had the " power of emitting a singing noise when 

 handled or disturbed, the noise being similar to that produced by 

 the common little beetle, Lema trilineata" Sanborn states (loc. 

 cit., p. 48) that the larva of Cressonia juglandis, which is found on 

 Carya alba and C. porvina, gives utterance to a note resembling 

 the sound tcep or tceep, produced by the inspiration of a small 

 quantity -of air between the upper teeth of the human mouth and 

 the lower lip, as in the act of sucking, and makes the same sound, 

 if held, a little behind the middle, whilst it turns the body sharply 

 from side to side. Sprague asserts (loc. cit.) that a similar sound 

 is produced by the larvae of Smerinthus excaecatus and S. geminatns 

 when irritated. Mead also confirms (loc. cit., p. 47) Reed's ob- 

 servations. We believe that it has somewhere been shown that 

 this noise is made by the jaws in the same way as a cracking sound 

 is made by releasing a fingernail from under that of the thumb. 

 Fernald observes ( Sphingidae New England, p. 94) that the larvae 

 of some species are so numerous at times in America that the 

 amount of damage done by them far exceeds anything that could 

 be imagined. 



Newport has shown that the larva of Sphinx ligustri increased 

 from -gL of a grain on hatching to nearly 125 grains (when fullfed 

 32 days after), an increase of 9976 times its original weight, and 

 further asserted that growth is most rapid after the last moult, and 

 that a larva of the same species increased from 20 grains to 120 

 grains during its last stadium extending over eight days. 



Considerable detail relating to the moulting of the Sphingid 

 larvae has already been noted (anted, vol. ii., pp. 5, 19, 27 — 30, 

 32) chiefly, however, relating to the larval pupal moult. Speaking 

 of the exuviation of Sphingids, Reaumur notes (Mem., ii., p. 255) 

 that " the larvae which have a caudal horn leave it with the cast 

 skin, a new one being developed with the new skin." Watching a 

 larva of .S. ligustri changing its skin, he waited until the anterior 

 part of the body and the prolegs had been withdrawn, and the 

 old skin was pushed well back posteriorly, but the caudal 

 horn was not yet clear. To see whether the new caudal horn was 

 contained within the old one, he cut the latter as low down as 

 possible, and when the moulting was complete he found that "the 

 new horn had been mutilated and had lost half its length, showing 

 that the new horn was contained in the old as in a case." Chapman 

 observes (anted, ii., p. 19) that, at the moult to pupa, before the 

 larval skin is exuviated, the relative size of the segments has much 

 changed, the prothorax being large, the first abdominal very small, 

 whilst he observed that the margin of the mesothorax against the 

 prothoracic spiracle was already brownish as well as the flanges on 

 the 5th, 6th, and 7th abdominal segments. [Further details of the 

 moult are given loc. cit., p. 32.] 



