INVESTIGATION OP THE PUSS MOTH 305 



whicli the head can be enclosed, but passing over the 

 resemblance to a face. He explains the mechanism by 

 which the tails can be protruded and withdrawn, offering 

 the very probable conjecture that they are used to drive 

 away ichneumons. He compares the cocoon to a wooden 

 box, in which the pupa lies secure, and shows that it is 

 made of fragments of wood cemented together by saliva. 

 Then comes the puzzling question : — How does the moth 

 extricate itself from the hard shell, within which it under- 

 goes its transformation? Reaumur could only guess 

 (rightly, as it happened) that it secretes a liquid which 

 softens the cement. 



De Geer^ discovered a transverse slit beneath the 

 head of the larva, from which an irritating fluid could 

 be ejected. Once when he happened to touch the larva, 

 it shot into his face two jets of a clear liquid, some of 

 which entered his eye, and for a short time caused sharp 

 pain. He dissected out the reservoir from which the 

 liquid is discharged, and remarked that captive larvae 

 soon lose the secretion or the power of ejecting it.^ He 

 makes also the interesting observation that the puss- 

 moth larva is sucked by small flies, which become dis- 

 tended by its greenish blood. The caterpillars seemed to 

 feel little or no pain, and no affcer-efiects were perceived.* 



Bonnet* describes the slit behind the head of the 



1 Hist, des Insectes, Vol. I, p. 324. 



" In another place De Gteer describes the ejection of a liquid by the larva of 

 the willow saw-fly, but his observations seem to have escaped the notice of 

 those naturalists who have in recent times discussed the case of the puss-moth 

 larva. He says that the saw-fly larva, when touched, can throw out several 

 jets from the sides of its body, in a horizontal direction and to a distance of a 

 foot or more. The liquid is clear, of greenish colour, and of a disagreeable 

 odour. Captive larvae lose the power of ejection. The pores by which the 

 liquid issues are situated just above the spiracles. (Vol. II, pp. 936-7.) 



' The flies were perhaps those of Simulium. 



*Sav. Strang., Vol. II, p. 276 (1751) ; (Euvres, Vol. II, pp. 17-24. 



U 



