254 



INSECT TRANSFORMATION 



bristle-tail, but specially adapted to the mayfly-larva's aquatic 

 habit of life. Bristle-tails may with high probability be 

 regarded as the most primitive of insects now living, and the 

 mayfly-larva resembles them not only superficially, but in 

 such important characters as the jaws, limbs, and abdominal 

 appendages. It may therefore be permissible to regard as 

 the most primitive type of insect larva, a form like the mayfly 

 grub before it had become modified for breathing dissolved 



o 



' 



FIG. 122. FIRST-STAGE LARVA OF PRIMITIVE MOTH (Micropteryx Caltkella). 



a, dorsal view ; b, side view, x 65. c, thoracic leg ; d, abdominal pro- 

 leg of later larva, x 200. e, abdominal proleg of first stage larva, x 600. 

 After Chapman, Trans. Ent. Soc. 1894. 



air ; that is to say with the abdominal appendages not 

 specialized into flattened plates, but slender and probably 

 jointed. 



~VThe most primitive type of beetle-larva resembles this in 

 general form, and in the presence of recognizable maxillulae, 

 but has lost all the series of abdominal limbs, while its man- 

 dibles are of the normal insectan type like those of its parent 

 beetle, which it may also resemble in its two-clawed foot. 



