98 
Psyche 
[March 
thrust and pressure of the gonapophyses in the endandrium are addi- 
tional (perhaps necessary) factors in the eversion and erection of the 
aedeagus. Contraction of the annular musculature of the aedeagus 
itself additionally extends the organ and causes the tip to inflate 
into a bulb, bilobed dorsally, which abruptly terminates in a conical, 
or nipple-shaped tip upon which the ejaculatory duct opens (fig. iD). 
The fully extended aedeagus runs between, and is guided by, the 
smooth inner faces of the gonapophyses and the ventral surface of 
the ovipositor to enter the common oviduct, from the anterior ventral 
margin of the orifice of which extends a chitinous guiding flap that, 
at other times, closes the aperture (fig. i'C). Once entered into the 
oviduct, the apical bulb of the aedeagus is inflated within the vesti- 
bule of the common oviduct which opens at the junction of segments 
IX and X. In that position the ventral bulge of the bulb evidently 
blocks off the common duct of the tubular accessory glands of the 
oviduct, and the conical tip of the aedeagus enters the short sper- 
mathecal duct, within which there is a minute sclerotization (fig. 9, 
Cooper 1972). Insemination therefore takes place directly into the 
duct of the spermatheca. 
The account just given will very likely be found to agree in its 
main features with the complex “reciprocal intromission” of other 
B'oreus, even though Martynova’s (1954) figures 1-6 hint that the 
endandrium may differ in depth and conformation among different 
species. However it is at variance with Steiner’s (1937) description 
(or inference?) for B. hy emails in which the tips of the gonapophy- 
ses are said by him to be received directly and separately into the 
pockets of the epandrium. That is not the case in still other mated 
Boreus (B. hrumalis, B. nivoriundus) that I have studied, and in 
which endandrial insertion occurs. Nor is it likely that the condition 
observed by Byers (1954) in a preserved, mated pair of Boreus uni- 
color Hine is a normal state of affairs; namely that the tips of the 
gonapophyses are bent across one another, and are held thus by the 
gonostyles of the male at right angles across his epandrium. Nor does 
B. notoperates conform to Potter’s (1938b) description for B. hy- 
ejnalis of a coiled or folded ductus ejaculatorius (see her fig. 30) 
which, at rest, is thrown into three flexures within the genital cham- 
ber, and which is evaginated during coition. As Steiner said, the 
intromittant organ is strongly muscular, and as I have shown it is in 
effect erected without evagination comparable, say, to that of a true 
internal sac. The element which Potter figures in front of the first 
distal flexure, appearing continuous in her figure with the “ejacula- 
