1875. 67 



is so dark iis to appear almost black, (hough in nality the sides ar(> darker than the 

 back, especially towards the spiracles, where the blackest part being in contrast with 

 the pale jellowish-white stripe below, makes it appear very brilliant ; the black sub- 

 dorsal streaks have now become thickened into wedge-shapes, broadest at the twelfth 

 segment, where their bases arc only separated by the thin and much interrupted 

 yellowish-grey dorsal line : at this stage, in their captivity, it was that the precocious 

 individuals began rapidly to increase in size, and attain full-growth in autumn, some 

 of them keeping almost black to the last, others showing a mouse-coloured ground 

 tint, more or less between the black markings ; in these lighter examples the black 

 marks were greatly reduced, in two instances to the merest rudiments. 



The full-grown larva measures nearly two inches in length, stout in proportion, 

 cylindrical in figure, though tapering a little at the thoracic segments to the head, 

 which is the smallest segment ; the thirteenth, sloping down from the back, tapers a 

 little towards the end which is rounded off ; the general appearance is plump and 

 full, though the segmental divisions are very well defined, and the two usual trans- 

 verse wrinkles towards the end of each segment can, in their plumpest state, be 

 generally seen. 



As regards colour, the head is usually brownish-grey, streaked on tlio front 

 margin of each lobe, and reticulated at the sides, and freckled above the mouth, with 

 blackish or with dark grey ; the ground colour of the body varies in individuals from 

 a light mouse colour to the deepest greyish-brown ; on the second segment is a semi- 

 circular smooth, but dull, plate of rich reddish-brown edged with black in front, 

 through which runs the beginning of the usual lines, which arc also continued faintly 

 through the similar brown-coloured anal flap ; the dorsal fine line is in most cases 

 pale yellow, sometimes, at the very last stage, seen quite uninterrupted, but often 

 much obscured ; the yellow sub-dorsal line, a trifle thicker, runs its course in a 

 festooned manner, when visible, forming a series of curves, the end of each curve 

 bearing the hinder tubercular yellow dot ; the dots, in threes on either side of the 

 back of each segment, are always visible, and sometimes dingy ochreous-yellow, but 

 the sub-dorsal line is sometimes absent ; within the sub-dorsal lino on the back of 

 each segment, in front, is a more or less broad, black, velvety, blunt wedge-shaped 

 mark, and the ground colour between these marks often so thickly covered with 

 blackish coarse freckles as to give a blackish appearance to the whole area of the 

 back ; on the side, as far as the spiracles, the ground colour is often quite as much 

 obscured with black freckles, while in some examples this part is freckled equally 

 with yellow and black ; but it is always bounded below by a vclvety-blaek fusiform 

 or triangular mark, bearing just within its lower edge the black spiracle, which, 

 tliough not readily seen, may often be observed to be delicately margined with grey; 

 immediately beneath comes the broad stripe of consjjicuously bright yellowish-white, 

 narrower on the second segment, and widening gradually to the Cflh; suffused in 

 the middle of each with a tinge of orange or of pink, and having a chain-like series 

 of blackish and grey freckles running through its middle : the belly and legs of the 

 ground colour are generally much paler than the back, but freckled with black at the 

 sides, more sparingly towards the middle. 



Among the larva; sent me by Mr. Blackburn, some beautiful varieties were 

 developed. Directly after their last moult they seeniod to be qiute black and velvety, 

 but with a brilliant sub-spiraeidar wliilisli stripe, as the skin became more expanded 

 by their increasing growth, the gx'ound colour began to appear by degrees on the 

 back and sides, in the interstices of tiie black freckles, of a cool grey tinged willi a 

 rusi) hue, and banded aero.-d the front of the beguients witii a sufl'usioii of blackish- 



