468 



TRANSFORMATIONS OF INSECTS. 



more elaborate and complicated than those of the full-grown 

 males and females. 



The central figure represents a newly-born larva or Nauplms 

 form ; that on the left is of a Zoca, after a moult, and the 

 perfect female is shown upon the right hand side of the en- 

 graving. 



These creatures may be found in the adult form upon the 

 eyes, skins, and gills of many fish and Crustacea, and adhere by 

 the matter which is formed upon the arched ends of the projec- 

 tions in front of the straight part of the head, which is sur- 

 mounted by two small antennae. The head, body, and abdomen 

 are united, but there are constrictions which divide them to a 



THE METAMORPHOSES OF A LerucEan {Tracheliastes polycolpus). 



certain extent, and the intestinal canal may be noticed running 

 down the midst. The female, at certain times of the year, has 

 two long ovisacs at the end of the abdomen, for the reception 

 of eggs which are developed within the body, but the limbs do 

 not ""exist. The only exception to this statement is the arched 

 structure ended by the sucker in front of the head, and probably 

 this is formed by a pair of altered extremities. The LerncBa 

 lives upon the juices of the fish, to which it adheres, and it pro- 

 duces ova which in due time escape. 



The Q-ZZ consists of an outer and inner membrane ; and the 

 embryo, which before hatching is more or less globular., is fur- 

 nished with an eye and two pairs of oar-like legs, the second 

 pair being subdivided, and all ended with bristle-shaped hau's. 

 The embryo bursts forth, and a Nauplins or early lai-va, like 

 that figured in the engraving, results. The legs are more fully 



