24 W. H. FURLONGE ON THE PULEX IRRITANS. 



inwards by the retraction of the fleshy organ to which it is attached 

 forming flaps, of an inverted V shape, as shown in Fig. 10, or they 

 may be expanded or opened out in a most extraordinary manner, 

 presenting a notched or embattled outline or margin, in which posi- 

 tion it is seen to be furnished with three curved spines, as shown in 

 Fig. 9. The contraction and opening out of the extremity of the 

 organ are accomplished very suddenly, and with considerable 

 force. 



The opposite or inferior extremity of the sheath is connected to 

 a pair of bands, or rather rods, of dark brown chitin, which curve 

 upwards and then backwards into a coil of several turns, like a 

 spring, as, in fact, there can be no doubt is precisely the purpose 

 which these curved and coiled rods really serve, extruding the 

 penis sheath by uncoiling, and retracting it by the opposite action, 

 the coiled state being the normal position of the rods. 



The Penis. — Looking down upon the extremity of the extruded 

 sheath, when expanded, a minute orifice may be observed through 

 which the penis is projected. It is a dark -coloured, wire-like 

 organ — presumably chitinous — which is capable of protrusion for 

 about half the length of its sheath ; but of its structure I can give 

 no further descrijDtion ; in fact, I have only seen the extrusion of 

 the organ in some four or five instances out of the dozens of male 

 fleas I have had under observation, and on these occasions it was 

 protuded and retracted with such rapidity that the eyes could 

 hardly follow it. I have no doubt, however, that it constitutes one 

 of those coiled rods or chitinous fibres just described, and that it is 

 projected by the uncoiling, and withdrawn by the release of the 

 spring-like coil. I have been entirely unsuccessful in my attempts to 

 distinguish the spermatic vessels of the male pulex, unless they 

 may be certain glandular organs filled with transparent globules, 

 situated around the spiral coil; but it is difficult, if not impossible, 

 to distinguish any difference in structure between these and the or- 

 dinary fatty globules abundantly found aglomerated together in 

 many parts of the internal organs. 



Having now described the organs of reproduction, it remains to 

 describe their office. The first action is the extrusion of the 

 sheath plates and forceps. These latter grasp the plates which, as 

 already described, project on either side of the extremity of the 

 abdomen of the female, and thereby the male is enabled to take 

 firm hold of the female insect during copula. The extrusion of 



