18S4.] 197 



of pale skin, a similar brown plate is on the anal flap. When twelve 

 days old, the internal vessels appear full of food, and as the size 

 increases the alimentary canal acquires more and more of a dark grey 

 colour, showing very plainly through the clear almost colourless skin. 

 When six weeks old they become of a dingy grey-brown colour, 

 almost approaching to blackness. On 25th September, I chanced to 

 notice one larva, which appeared nearly ready to moult ; it was then 

 dark grey-brown at each end, and whitish-grey along the middle 

 segments of the body, where the dark dorsal vessel showed through, 

 but interrupted at the segmental folds of pale skin ; this larva I kept 

 apart, and in a few days it moulted, and became as dark as any of 

 the others. 



On 27th September, the smallest was from 9 to 10 mm., and the 

 largest 13 mm. long ; the head jet-black, the plate nearly as black, and 

 also three or four following segments, this hue from thence melting 

 gradually into slaty-grey, whereon the minute tubercular black dots 

 appeared ; the anal plate brownish-black, and dull. The individual 

 kept apart from the others had increased to a length of 17 mm. by 

 the nth of October, when it was of a slaty blackness. By 13th of 

 November, most of the others had grown to be 20 mm. long, inhabiting, 

 as I said before, long soft tubes of dark grey-brown silk, smooth inside, 

 but covered externally with quantities of the sweepings ; the larvae I 

 turned out to inspect were now entirely black, excepting the pale upper 

 lip, papillas, and the legs, which were all semi-pellucid and light drab- 

 coloured ; a great number of pellets of black frass appeared in the 

 pots, these I was careful to remove on all occasions of replenishing the 

 supply of sweepings. 



I did not disturb them again until 4)th of March, 1883, after 

 keeping them through the winter in a cool dark place, and then I found 

 they had not grown at all in the interval, but during the next twenty 

 days their tubes increased to a length of two and a half inches, and 

 the agglomerations adhering made up roughly a transverse diameter 

 of about three quarters of an inch. 



As stated above, all this investigation of the growing larvae was 

 made at the cost of the lives of most of them ; however, at the end of 

 April, there still remained two alive, and from them, and also from other 

 examples captured when mature, I made the follawing description. 



The full grown larva is from 25 to 29 mm. in length, almost 

 uniformly cylindrical throughout, though rather stoutest at the third 

 and fourth segments, which have deeply sub-dividing wrinkles, and on 

 each of the following segments to the twelfth is one deep transverse 



