330 ME. P. H. GOSSE OX THE CLASPING-OEGANS 



office of the ordinary valves is to some extent supplied by this thatching, the valves 

 being almost aborted. 



The uncus is here a stout, short, bifurcate process, the two points not quite equal 

 inter sp, acute, notched below. They are followed by a couple of pear-shaped organs, 

 of highly polished, glittering, brown chitine, each terminating in an oblong knob, beset 

 with minute spinous teeth. In fig. 21, they are seen in .s'dit ; in fig. 22 the right is seen 

 interiorly, showing that it consists of a hollow shelly ease, with the edges curved-over. 

 The knob bends upward, toward the bifurcate uncus, but comes considerably short of it (as 

 shown in fig. 21, where both the right and left knobs are seen), whereas in P. Diplal/ts 

 the knobs close on the truncate tip of the uncus. 



There can hardly be a doubt that these organs are homologous with what I have called 

 "valveless harpes," in Diphilus. But, tracing them to their origin, we find that they 

 spring from a point on each side, within the descending rami of the uncus, i. e. within 

 the walls of the ninth segment; whereas the valves are appendages of the eighth, and 

 are always outside the walls of the uncus *. Thus it is perhaps possible to consider these 

 spinous knobbed organs the homologues of the teeth of the scaphium, which (in P. 

 Merope) we have seen to be serrated. The scaphium itself I do not find in P. Polydorus, 

 unless it is a shining white mass (in texture like the white of an egg boiled hard), into 

 which the pear-shaped organs merge at their bases. 



What I suppose are the col res proper (or their representatives), are a pair of organs 

 (seen /'// situ, in fig. 21 below the pear-shaped bodies, with the penis protruding from 

 between them) which certainly spring from the bottom of the eighth segment. Fig. 23 

 represents one of them, the left, viewed internally ; it bears a semitubular ridge of chitine 

 running through its midst, terminating in a minute point. This (supposed) valve is 

 hollow, and is beset, on both margins, with long straight bristles. 



If this analogy is true, it must be true also in P. Diphilus ; but the application seems 

 more difficult there. 



It may be interesting to compare De Haan's description with mine above, every 

 word of which, I may say, was written before I saw his. He says, "P. Liris and P. 

 Polydorus have the hinder part of the body naked; the valves [kleppen] are very 

 short, armed from within to the top by a hook [?, P. II. G.], and the lateral appendages 

 [zijdelingsche aanhangsels] of Amphrisius t are placed under it : the spine on the back 

 is blunt [uncus ? P. II. G.] ; besides this, there are also two spines present on the 

 upper edge, and these are curved inwards ; so that, altogether, the outer edge is provided 

 with seven appendages J, which all rise free from one another. Between these lies the 

 penis [roede], which, as if pressed together, has a sharp edge above and below "§. 



* The harpe however, has a double basis normally first to the valve, secondly to the knob which projects from the 

 floor of the genital cavity. This latter is, I think, situate within the ninth segment. 



t These are, I presume, what I have called the harpes in Ibis Memoir. 



J If I understand him, I can find but six : viz. the two points of the bifid uncus, the valveless harpes (or sca- 

 phial teeth) ; and the two bristled valves? Hut I am not sure that I follow his identifications. He seems to imply a 

 terminal point to the uncus, besides and between the two points which alone I find in Polydorus ; and in his figures 

 of Liris he represents such a point. Polydorus he has not figured. Possibly he did not examine both minutely. 



§ Nat. Gesch. Ned. 0. B., Tapilionidea, p. 17. 



