NOTES ON THE POPLAR SAW-FLY 



153 



greenish colour of the larvae a tinge of orange appeared on 

 the first three and segments ten and eleven of the abdomen : 

 black spots also made their appearance at this stage, two 

 on each segment. As the caterpillars fed and moulted the 

 orange colour became more general until after the last moult, 

 when fully grown, the entire body was orange in colour. 



The full fed larva varied from 18 to 20 mm. in length, with 

 dark brown head, thorax, and abdomen of a bright orange 

 colour, and each segment bore two black marks on each 

 side of the body, the lower of the two being considerably 



LI B 



Fig. 3. — Damage by Older Caterpillars. 



smaller than the upper. The caterpillar was clothed with 

 numerous white feathered hairs. 



Types of Feeding. — When the young larvae reached the 

 fourth instar they became more active and wandered from 

 leaf to leaf, feeding singly or in twos and threes but not in 

 serried ranks, as at the earlier stages of their life. A leaf 

 was attacked usually from the edge, the larvae lying on the 

 plane of the leaf and eating steadily backwards, leaving only 

 a few of the chief veins untouched. In this way the entire 

 leaf was often destroyed (Fig. 3). Again, the older larvae 

 also gnawed holes in the leaves, not necessarily commencing 

 feeding at the edge. As in the case of the younger stages, 

 they also fed from the underside. The larvae when full 



