THE LIFE HISTORY OF ANCYLIS UNCANA. 127 



of this, because I had two larvae under observation, and in 

 neither of them could I detect a change into a fourth instar ; 

 still I cannot be quite certain on the point, because it is always 

 very difficult to keep a concealed larva so completely under 

 observation as to ensure detecting all its changes. 



The full-grown larva is 11 mm. long, the greatest breadth 

 is 1"6 mm.; the head is polished, amber-coloured, with black 

 markings round the mouth, it is distinctly narrower than the 

 prothorax ; the prothoracic plate is polished light greyish-green, 

 the rear portion has on each side of the medio-dorsal line a 

 black blotch, the broadest end of which is towards the dorsal 

 line, and it tapers to a point laterally. Below these blotches on 

 each side of the prothorax are two elongated dark blotches, one 

 above the other ; the prothoracic spiracles, which are black, are 

 much larger than the other spiracles, and immediately behind 

 the upper of these blotches, and on the rear of the prothorax. 

 The prothorax itself is distinctly narrower than the mesothorax. 



The remainder of the segments are light greyish-green and 

 transparent, the dorsal canal showing plainly ; the tubercles 

 are very prominent, dark grey, with a jet-black centre, which 

 emits the usual spine ; the prolegs are greyish-green with 

 minute dark spots and markings ; the anal plate is hardly 

 visible. The spiracles are minute and jet-black. "When the 

 larva is full fed it wanders about until it has found a dead leaf, 

 with which it forms a pocket to hibernate in, similar to the one 

 in which it has fed. 



On July 27th the majority of the larvae were evidently 

 hibernating in pockets in dead leaves, but one had pupated in 

 a pocket in a green birch leaf, and on August 18th the imago 

 emerged. 



This pupa was 7 mm. long, with a greatest breadth of 

 1'5 mm., and of average stoutness; the segmental divisions 

 were clearly defined, the surface was smooth without noticeable 

 hairs, the head nnd thoracic segments were smooth and highly 

 polished, and dark brownish-green in colour ; the antennae and 

 leg cases were highly polished and concolorous with the 

 thoracic segments ; the abdominal segments were slightly 

 polished brownish-green. These segments have dorsally a row 

 of blackish raised spikelets, projecting backwards; the anal 

 extremity was blunt and armed with several hooks. 



On January 24th last, two of the larvae were examined and 

 found to be unchanged. On March 21st they were again 

 examined, when unfortunately, they were discovered to have 

 been devoured by some predacious creatures, probably woodlice. 

 There does not seem to be any doubt however but that they 

 hibernate as larvae, and pupate in the spring. 



There can be no question but that the larva feeds only upon 

 birch ; I tried them upon the other two plants growing when 



