U. H. F. Nuttali. 
•297 
the last abdominal segment and appears to be retractile into a tube 
lying within the body. This tube bears teeth, as does the vagina, the 
teeth pointing anteriorly. Landois’ figure agrees with his description, 
both being partly right and partly wrong. 
Patton and Cragg (1913, p. 540) somewhat vaguely describe the 
organ as “of a comparatively simple type” consisting of “two pairs of 
chitiiious rods lying in front of each other in the terminal segment of 
the abdomen and articulated on a moveable joint.” The posterior 
pair of rods converge behind,, “are in close contact with one another, 
and convey the ejaculatory duct to the exterior between their inner 
surfaces.” The musculature is complicated. This description is cryptic 
and mostly wrong. The authors’ “anterior pair of rods” are what is 
termed the basal plate, the “ posterior pair ” are the parameres, or what 
in this paper we term the dilator. The authors apply the name of 
penis to both of these structures combined. 
Pawlowsky (1907, p. 30) illustrates his paper by cross and longitudinal 
sections of the male which are more enlightening than his text He does 
not appear to have understood the mechanism any better than the 
preceding authors, to have made dissections, or to have studied the 
living insect. He refers to the teeth upon the “ enveloppe de propulsion ” 
which he thinks holds the “penis” in place in the vagina; what he terms 
the penis are the combined basal plate and dilator. Pawlowsky’s 
figmes are good, for he evidently made faithful drawings of what he 
saw. 
Mjoberg (1910, p. 252), although he does not mention Pediculus, 
compared the male copulatory organs in Anoplura and Mallophaga. 
He is the first author who seems to have understood the structure in 
the allied forms which he studied. 
Leaving the testes and vesiculae seminalis aside for future considera¬ 
tion, we find that Mjoberg states that these insects usually possess a 
copulatory apparatus consisting of (1) a long duel us ejaculatoiius, 
(2) a basal plate (in some Amblycera represented by two long free rods), 
(3) parameres, either free or more or less fused (probably serving to 
widen the vulval aperture to allow the copulatory apparatus to enter), 
(4) a “preputial sack,” studded vfith small chitinous knobs. In Ano¬ 
plura and IcHNOCERA, the male carries the female on his back, intro¬ 
duces the parameres, then everts the preputial sack which bears an 
apical penis that penetrates into the female. The chitinous knobs upon 
the sack anchor the organ to the vaginal wall. Copulation appears to 
last a long time. 
