G. H. F. Nuttall 
321 
recurved ventral spur near the base of the femur. This spur serves to 
facihtate and maintain the grip of the male claw upon the leg. 
In conclusion, a glance at Plate IV will serve to recapitulate the 
main points regarding the structure and interrelations of the copulatory 
apparatus in both sexes of Pediculus humanus. The figure is printed 
in two colours to differentiate the parts belonging to each sex, black for 
the male and red for the female. The figure represents a camera lucida 
drawing of a specimen mounted in balsam and confines itself to the 
chitinous structures. The terminology of the parts will be found 
accompanying the other figures described in the text. 
Fig. 12. Pediculus humanus $ Portion of the third leg, showing the ventral spur upon 
the femur which aids the male to grasp the female. Camera lucida drawing of tire 
leg in profile. 
The manipulations of kilhng and mounting the insects led to the 
male relaxing his hold with his claws, and, in consequence, their bodies 
became somewhat separated, the dorsal surface of the male and ventral 
surface of the female being uppermost in the illustration. The 
copulatory apparatus of the male occupies the greater part of the lumen 
of the vagina, although the male organ has been somewhat retracted. 
The parts of the male lying within the vagina are stippled and the 
teeth covering a corresponding area on the surface of the vaginal wall 
are omitted to avoid confusion. It may be regarded as certain that 
the vesica fills the whole vagina in fife and the presumption is justified 
that the penis enters the lower part of the uterus. The illustration 
further elucidates some details in the structure of the male apparatus. 
Dotted fines indicate the course of the ductus ejaculatorius from above 
the dorsal plate through the vesica to the tip of the penis, dorsal to the 
