THE ENTOMOLOGIST. 339 



" Some young friends of mine having brought me a fine 

 specimen of llie larva of Cossns, I was curious to know the 

 nature of the milky fluid the insect threw up in the bottle in 

 which it was confined. A portion, dried upon a glass plate, 

 being submitted lo one of Ross's achromatics, was found to 

 be i)in'e starch, ])olarized light showing the black cross very 

 beautifully on each grain. I had hitherto imagined that the 

 larva of Cossns consumed the wood of the trees into which it 

 bored : it appears, however, more nice in its appetite, ex- 

 tracting the nutritious juices only. In this experiment 1 was 

 struck with the amount and purity of the starch." (Zool. 2612). 

 1 have no doubt, however, that the sawdust which we find in 

 the galleries of the goat-moth has actually passed through 

 the alimentary canal, the starch being extracted in its 

 passage. 



The full-grown larva is 3^^ inches in length, and about 2 

 inches in circumference ; it is very maggot-like in appearance ; 

 the head is flat, porrected on the same plane as the body and 

 rather rugose ; the mandibles are arched and very powerful : 

 the body is depressed and wrinkled both transversely and 

 longitudinally : there is an appearance of its having fourteen 

 segments, an appearance only, and produced by a division 

 or fold of the 13th : everj' segment, not excluding the head, 

 emits ten, twelve or fourteen rather strong bristles ; and the 

 2nd segment has a smooth dorsal plate of intense hardness. 

 The colour of the head and of the plate on the 2nd segment 

 is black ; the latter is divided by a longitudinal medio-dorsal 

 line into equal halves, each of which projects a large lobe 

 towards the posterior extremity of the larva; the rest of the 

 body is rich ochreous cream-colour, with a very broad 

 purple-brown medio-dorsal stripe : the spiracles are brown, 

 and each is deeply seated in an oval cup-shaped cavity 

 which is edged with brown. 



Having attained its full size, the caterpillar amuses itself 

 by lining its burrow with a thin coating of silk, for what 

 purpose 1 know not; and it also Sjnns within its burrow or 

 gallery an oblong cocoon, composed of silk and sawdust, the 

 sawdust being of its own niauufacture, alliiough probably not 

 ])repared for this especial purpose. Ti)is cocoon is so ex- 

 cessively tough that it cannot be torn ojien without the 

 greatest diflSculty. In this retreat the caterpillar often 



