Genera Priotyrannus and Cacoscelcs. 375 



The other tliree agree with the figure and description which 

 Thomson has given of the species. 



Thomson and Ltacordaire must have either overlooked or 

 misunderstood White's description of the mandibles, for no 

 mention is made by them of the diiference in form. 



The first form is well shown in the figure given by Tliom- 

 son (Arch. Entom. i. pi. x. fig. 1) and is fully described in 

 Lacordaire's characterization of the genus. 



The second form fully resembles that of the female, but is 

 somewhat larirer in size. 



o 



The female of the species was unknown to Thomson and 

 Lacordaire, while White's reference to it is both inaccurate 

 and incomplete. The following are its characters, taken from 

 some fine specimens from the Animallai Hills : — 



Mandibles broader than thick, narrowed to an edge on the 

 inner side, provided with teeth along their whole inner edge, 

 strongly curved in and terminating in a sharp point at tip, 

 meeting along their whole length when closed. Head and 

 prothorax coarsely rugosely punctured as in the male ; the 

 lateral spines of the prothorax exactly as in the male, but 

 with the spine at the anterior angle somewhat feebler. 

 (White's description in this respect is quite misleading.) 

 Elytra as in the male. Antennas much slenderer than in the 

 male, not surpassing three fourths the length of the elytra, 

 with the first six joints smooth, glossy, and sparingly punc- 

 tured, the remaining joints dull and marked with fine longi- 

 tudinal striations. The last ventral segment of the abdomen 

 is slightly elongated and is rounded at the apex. (In the 

 male this segment is much shorter and broader and is nar- 

 rowly and sinuately truncated at the apex.) 



In addition to the four specimens mentioned there is in the 

 Museum collection a very small male from Bombay with 

 mandibles of the female form. It is much darker in colour, 

 nearly black, but does not otherwise seem distinct. I have 

 not seen any specimens of this genus with distinctly inter- 

 mediate forms of mandibles. 



On extending my observations to allied genera I found a 

 variation of precisely the same character in the African genus 

 Cacosceles, as exemplified by some specimens of C. Lacor- 

 daireij Bates. Here were males with the female forms of the 

 mandibles and males with intermediate forms. This was the 

 more interesting as Lacordaire had, apparently with great 

 confidence, described as females some of the intermediate male 

 forms. The female is in fact very different from the male ^. 



* For excellent figures of both sexes and descriptions of tlie females see 

 Periugue}", Trans. 8. African Pliil. Soc. iii. p. 145, pi. iv. figs. 1-4. 

 These descriptions had escaped my attention hitoie writing the above,. 



