298 
Sftifliefi on Pediculns 
We are indebted to Mjoberg (1910, p. 226) for giving us a nomen¬ 
clature of certain parts of the male copulatory apparatus in Anoplura 
and Mallophaga. To repeat somewhat, these parts are (1) the hasal 
plate, articulating distally as a rule with more or less free structures, 
the ductus ejaculatorius always running dorsally to the plate; (2) the 
parameres (a term taken from Verhoeff, 1903, pp. 113-170 (cited by 
Mjoberg), who used it in relation to Coleoptera), these being accessory 
parts articulating upon the distal portion of the basal plate; (3) the 
preputial sack which surrounds the penis and distal portion of the 
ductus ejaculatorius and appears usually to be attached to the distal 
part of the basal plate between it and the parameres. Mjoberg supposes 
that the preputial sack, like the penis, may have originated from the 
ninth and tenth intersternital cuticle. (In Haematopinus suis, Mjoberg 
noted the great length of the narrow ductus ejaculatorius and its uniform 
width, but failed to trace it into the penis.) 
Muller (1915, pp. 41-43, figs. 24, 25 and plates ii, iii) describes and 
figures the male genitalia. Confining ourselves to the copulatory organs, 
we find that he describes the ejaculatory duct as entering a copulatory 
apparatus so complicated that “even Pawlowsky did not fathom it.” 
Muller describes it as a deeply invaginated apparatus with chitinous rods, 
plates, and teeth, but gives no account of these structures. He refers 
to the parameres (what we call the dilator) as the penis and says that 
the term “preputial sack” is a misnomer; in his opinion it should be 
called the “sac interne,” following Jeannel’s nomenclature applied to 
beetles’^. It is clear that Muller did not grasp the significance of the 
structure as a whole. He gives figures similar to those of Pawlowsky, 
a longitudinal section of the posterior extremity of the male abdomen, 
which is accurate but for the relation of the so-called penis to the sack. 
His interpretation of the function of certain parts is inaccurate. He 
denies that the sack contains the ductus ejaculatorius (as stated by 
Pawlowsky) and finds that the duct ends dorsally in the sack. We shall 
see presently that the duct runs dorsally to the sack when the latter is 
invaginated, but that it runs inside the sack when it is expelled. 
Cummings (1916, p. 257), hke Mjoberg, does not deal with Pediculus. 
He adopts Mjoberg’s nomenclature of the parts of the male copulatory 
* Vi<lc Sharp, D. and Muir, F. (15)12), “The comparative anatomy of the male genitalia 
in t'oleoptera,” Trani. Knt. Soc. London, p. 603. According to these authors, the sack is 
evaginatcdin Ooleoptera: it may have spines pointing basally, these preventing its with¬ 
drawal while distended. It is clear that the apparatus in beetles, though very different 
and varied in construction, has jpoints of re.semblance, functionally speaking, with that 
in Ferlicnl-ns, 
