672 Dr. T. A. Chapman on an 



or even produced into a blunt point. The rule in both 

 species seems to be for each scale to be accompanied by 

 two androconial scales, but in icarus it is not uncommon 

 for there to be three, a circumstance that is comparatively 

 rare in thersites, no doubt in accordance with the narrower 

 scales. 



The female genitalia present equally marked differences 

 with the male. There is in the female of these Lycaenids 

 a remarkable tube that in preparing the specimen can be 

 protruded from the orifice between the eighth and ninth 

 segment of the abdomen. I am not now concerned with 

 the anatomy and function of this organ, but here only 

 note that it usually terminates in a chitinous plate or 

 button, that differs more or less in each species. 



In A. thersites this terminal portion of chitin has a very 

 special form ; in P. icarus it is wholly wanting, or repre- 

 sented by a very minute chitinous plate, the only species 

 (of the few I have examined) in which it is absent. There 

 are other minor differences, but this one is very obvious 

 and very decisive as to the two species being well 

 separated. 



PI. LXXXIV, fig. 1, represents these parts in thersites, 

 fig. 2 those in icarus. 



A. thersites, notwithstanding its close resemblance to 

 F. icarus, is really much more closely allied to A. escheri. 

 I don't think any one is likely to confound these two 

 species, although, before I knew much about it, I queried 

 whether Thersites var. gravesi was not an Eastern form of 

 escheri, and though a leading authority on the Lycaenids 

 agrees, so far as the genitalia are concerned, thersites is 

 escheri. 



In this latter respect there is the constant difference 

 of size. It seems desirable nevertheless to figure the $ 

 genitalia of A. escheri, which shows a small but definite 

 and constant difference, especially in size, from those of 

 thersites, and especially photographs of the androconia 

 which differ from those of thersites more than do those of 

 icarus (pi. LXXXV). 



Of the few other species I have examined, damon 

 approaches most nearly to escheri and thersites in the 

 structure of this portion of the female appendages. Apart, 

 therefore, from its behaviour in the field as observed by 

 Herr Ministerial-Registrator Schreiner, by Mr. Tutt and 

 by myself, and from such evidence from the early stages 



