ON SOME LEPIDOPTEROUS LARV^ 79 



larva very sphinx-like in attitude, and with side stripes, 

 though these go in the opposite direction to the stripes of 

 the Hawk Moths. The larvae, when about one-third grown, 

 have a queer habit of crawling to the end of the birch twig, 

 when perhaps half a dozen will surround it and hang down 

 together like a tassel, with their heads slightly thrown 

 back, looking like a bunch of catkins or small half-opened 

 leaves. 



The larvse of that singular group of moths, the Sesias, or 

 Clearwings, and some others, feed internally in the wood of 

 trees, or at least inside the bark. As may be expected from 

 this habit they resemble in appearance maggots or the 

 larvgeof beetles rather than Lepidopterous caterpillars, their 

 jaws being strongly developed, whilst the legs are short, and 

 the prolegs or claspers almost rudimentary. Dwelling as 

 they do in dark galleries eaten out in the wood, they are 

 protected from many enemies, yet not from all, for some of 

 their insect foes are provided with means of searching 

 them out even as they lie concealed. On one occasion I was 

 looking for larvse of the Apple Clearwing {Sesia myopd^- 

 formis) in the bark of an old tree in a garden at Guildford, 

 which was honeycombed by the tunnels of many genera- 

 tions. Presently I became aware that I was not the only 

 searcher for the hidden larvse. A small ichneumon fly was 

 busily running up and down the trunk, working its antennee 

 constantly backwards and forwards. On finding a hole 

 which it believed was occupied by a larva, it would dart 

 down into it a long filament from its ovipositor, and if the 

 search proved successful the ovipositor itself would be in- 

 serted, to lay within the body of the haple-s grub the egg of 

 its destroyer. After watching the process for some time I 

 boxed the ichneumon, lest it should fly away. I now exhibit 

 it as a memento of the tragic straggle for existence which is 



