On the Ilymenopterous Genera Myzine and Plesia. 497 



interoibital bars, continued below tlie eye, the anterior edge 

 of tlie eye corresponding to the posterior part of the first bar. 



Hah. China. 



In the British Museum three specimens, 305 to 780 mm. in 

 total length. 



4. Cestracion amhoinensis. 



Heterodontus zebra (non Gray), Bleek. Act. Soc. Sc. Neerland. i. 



1856, Amboyna, p. 71. 

 Cestracion philippi (part.), Giintli. Cat. Fish. viii. p. 415 (1870). 

 Cestracion atnboitiensis, Regan, Anu. & Mag. Nat. Hist. (7) xviii. 190G, 



p. 436. 



. Dorsal fins more elevated than in any other species. Cross- 

 bars narrower and separated by wider interspaces than in 

 C. zebra and each split into two. Anterior edge of first inter- 

 orbital bar corresponding to anterior edge of eye. 



Bnh. Amboyna, 



In the British Museum one specimen, type of the species, 

 580 mm. in total length. 



LXXX. — Additions to the Ilymenopterous Genera Myzine 

 and Plesia. By Rowland E. Turner, F.Z.S., F.E.S. 



The genera Myzine and Plesia, though differing widely in the 

 female sex, are not distinguishable with any certainty in the 

 males, tiiough those species in which the basal segment of 

 the abdomen is very long and slender or nodose towards the 

 apex may be referred with certainty to Plesia, and those in 

 which it is very short and as broad as the second, almost 

 sessile, are equally certainly the males of Myzine. The 

 genus Myzine does not occur in America, and tliere is little 

 difficulty in distinguishing the males of the Asiatic species ; 

 but in Houtii Africa, where both genera occur plentifully, 

 some of the males cannot be assigned to either group with 

 any confidence. The length of the basal joint of the poste- 

 rior tarsi is no certain guide, as Saussure, who suggests that 

 some use may be made of tiiat character, recognizes. 



The two genera arc most strongly represented in Africa, 

 but the species oi' Plesia are fairly numerous in America, and 

 Myzine is well represented in the Mediterranean fauna and 

 in U'estern Asia. No species of either genus is recorded 

 from the Australian or Austro-Malayan regions; for Myzine 



