22 W. H. FURLONGE ON THE PULEX IRRITANS. 



I shall first describe — 



The Female Reproductive Organs. — The posterior lower abdominal 

 plate of the female flea is elongated or produced on either side so 

 as to form a V shaped recess projecting for some little distance be- 

 yond the body of the insect (Fig. 5). These lateral projections, as 

 we shall afterwards find, serve an important purpose during the 

 congress of the sexes. From the margins of these plates a fringe 

 of thick bristly hair projects inwards. The lower terminal portion 

 of the fleshy part of the abdomen projects between these lateral 

 plates, and upon its under side is situated a circular orifice fringed 

 with two rows of short hairs projecting inwards and outwards. 

 This orifice opens into a somewhat elongated vaginal canal, the 

 direction of which is upwards and forward. In the unimpregnated 

 insect, grape-like clusters of ovaries may be seen dependant from 

 the walls of the enlarged extremity of the vaginal canal, through 

 which, as will be afterwards seen, the male organ passes for its 

 entire length, thereby bringing the seminal fluid into direct contact 

 with the ovaries. After impregnation the walls of the ovarian cavity 

 distend enormously, so as to contain from six to ten exceedingly large 

 eggs, relatively speaking, which, when fully matured, appear to occupy 

 more than one half of the capacity of the entire abdomen. The 

 eggs of the flea are matured with great rapidity, and are produced 

 at the rate of five or six per diem, when the insect is in a state of 

 captivity ; but I have reason to believe that under natural condi- 

 tions they are produced even more abundantly. I have not had 

 opportunities of observing the development of the eggs in the 

 ovaries from the time of impregnation to maturity, this being one 

 of the points I have been obliged to leave unworked. 



The Male Reproductive Organs, so far as I have been able to 

 make them out, may be considered as consisting of three principal 

 parts — 



a. The prehensile organs and their sheath plates. 

 i3. The sheath of the penis. 

 7. The penis. 



Referring to Fig. 6, it will be seen that the inferior terminal 

 plate of the male flea is elongated so as to form a deep cavity. On 

 either side of this cavity are situated two rounded concavo-convex 

 plates of chitin, somewhat thicker in substance than those envelop- 

 ing the abdomen, but striated in a similar manner, the margins of 



