272 FEMPELIA FUSCA. 



For some days the larvae had been unaccountably 

 disappearing, but how and when I never could make 

 out, as their cage seemed close-fitting enough. By the 

 16th I bad only two or three left, and as these seemed 

 disposed to hibernate, I described the largest again, 

 as follows : — 



Length, three-quarters of an inch, and proportion- 

 ately stouter than when last described ; the segments 

 are rather plumper, and the wrinkled appearance of 

 the skin in the earlier stage partly lost. Raised 

 tubercles, too, have now made their appearance, but 

 are not very conspicuous. In other respects the 

 shape is the same. 



The ground colour is now a little paler, a distinct, 

 but very dark, olive tint is seen through the dull 

 black, and the alimentary vessel shows as a quite 

 black dgrsal line. The head, frontal plate, and 

 tubercles are polished, and black. There are no 

 other perceptible markings. The ventral surface 

 and prolegs are dull dark olive-green, and the legs 

 black. 



The larvae fed on the sallow leaves; but one I 

 found had evidently excavated the soft stem, causing 

 the leaves to droop and wither ; this was one of 

 the last larvae I saw, and suggested that it was 

 just possible that the disappearance of the other 

 larvae miofht be accounted for from their having been 

 thrown away unperceived in the old stems, though 

 I can scarcely credit that I overlooked them in such 

 a way. 



In the spring I could find none of the two or three 

 hibernated larvae, so made several journeys to the 

 heath, in order to complete the history of the species ; 

 but neither by sweeping nor by close searching could 

 I detect any trace of the larvae, which, however, may 

 perhaps be accounted for from the fact that three or 

 four excursions later for images only produced three 

 specimens, where the previous year they were in pro- 

 fusion. 



