3'22 
Studies ou. PefUmdus 
duct is shown the course of the anus to the rectum which opens im¬ 
mediately in front of the genital aperture. 
Note on the Nomenclature of Parts. 
In the foregoing description I have used some of the term.8 estabhshed 
by previous authors; most of these require no comment. The names 
applied to certain muscles are in accordance with their obvious functions 
as described in this paper. Several structures have been named for 
convenience of description and a few of these call for remark; namely 
the terms dilator, vesica penis and statumen penis: 
Dilator : this term is frequently used to denote the parameres, 
which, through the fusion of their distal extremities into a point con¬ 
stitute, functionally speaking, a single organ. The dilator corresponds 
to what all writers except Mjoberg and Cummings call the penis or a 
part of the penis. It is a composite structure whose derivation is 
discussed on p. 299. 
Penis : a term confined, in agreement with Mjoberg, to the chitinous 
tube which projects from the vesica (v. infra). 
Vesica penis, or simply vesica, is a term applied in lieu of “preputial 
sack” (Mjoberg) and “sac interne” (Jeannel) both of which are mis¬ 
nomers though supposed to be descriptive. 
Statunien penis is a term applied to the riblike chitinous thickening 
of the wall of the vesica penis {Statumen signifies a concrete object which 
causes a thing to stand, a support, stay, or prop). 
These terms are purely descriptive. In this connection Sharp and 
Muir *(1912, p. 485)^ ma}^ appropriately be quoted, they rightly say in 
writing of the copulatory organs that it is “premature to establish 
permanent terms for the parts of the complex genitaha of insects till 
the various Orders have been more thoroughly examined and com¬ 
pared.” 
' See footnote, p. 238. 
