CH. XVII. J VARIOUS SPECIES OF SAWFLIES 251 



gregariously, numbers feeding- upon a single leaf, 

 and the positions into which they throw their bod- 

 ies, when undisturbed, are often very extraordi- 

 nary ; indeed, the feats of muscular dexterity which 

 they exhibit are not less surprising than those of 

 our great posture-masters exhibited in our Christ- 

 mas pantomimes. Sometimes they will remain for 

 a great length of time standing, as it were, upon 

 their heads; others throw out their bodies in a 

 horizontal position ; while some assume the form 

 of an S, the tail being elevated in the air. 



These insects are said to be much affected by 

 falls of rain, which render the leaves upon which 

 they feed too moist, and which produce a kind of' 

 diarrhcea, causing them to die in a very short time. 

 Hence we may conclude that by watering plants 

 which are infested by them they may be got rid of 

 without difficulty ; fumigation by means of sulphur 

 has also been efficaciously tried. 



When the larvse have acquired their full size, they 

 generally let themselves fall to the ground, and bury 

 themselves beneath the surface, to undergo their 

 transformations. Here they generally spin an oval 

 silken cocoon ; some, however, content themselves 

 with merely forming an oval cell, by rounding the 

 earth in the immediate neighbourhood of their new 

 lodging, by violently striking their bodies against 

 the sides of the cell. Their proceedings may be 

 easily inspected by placing some of them, when 

 full fed, in a glass box, with a layer of earth at the 

 foot; and if this layer be sufficiently shallow, they 

 will descend to the bottom, and commence the 

 operation of forming their cells upon the glass sur- 

 face. Some species, however, affix their cocoons 

 to the branches of the trees upon which they had 

 fed. We may often observe a rose or gooseberry 

 bush entirely covered with these larvae, and in a 

 couple of days afterward not a single grub is to be 

 seen, neither are their cocoons to be found attached 



