28 



SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I31 



after completion of its own growth when the first chaHmus is de- 

 veloping beneath its cuticle. An insect larva in a corresponding stage 

 becomes quiescent and ceases to feed, but it is not a pupa. This con- 

 cealed period in which any instar begins its development within the 



Fig. 10. — Copepoda. Larval and adult stages of fish parasites. (A, B from 

 Heegaard, 1947; C, D from Wilson, 1905; E, F from Wilson, 1921a; G from 

 Wilson, 1917.) 



A, Caligus curtus (O. F. Miiller), second copepodid. B, same, transforming 

 stage of second copepodid. C, same, mature male chalimus. D, same, adult male. 

 E, Trcbius latijiircatus Wilson, adult female. F, Blakcanus cornigcr Wilson, 

 adult female. G, Hacmobaphes cyclopterina (Fab.), adult female. 



cuticle of the preceding instar has been termed by Hinton (1946) 

 the pharate, or cloaked, phase of development. 



The young chalimus that emerges from the copepodid cuticle is not 

 particularly different from the copepodid, though it is somewhat more 

 advanced in development. Its first concern is to reattach itself to the 



