92 
Psyche 
[March 
the gonostyles are returned to a grip on the posterior legs, near the 
coxae, and the male rests. When at last the ovipositor has been 
grasped, the gonapophyses are pried down and slightly apart, the 
female holding them, as though plastic, in whatever position they 
were released by the gonostyles. The gonapophysis of each side is 
then engaged between the inner tooth and the tip of the corresponding 
gonostyle which, on adduction, directs and thrusts the tip of the gona- 
pophysis into a pocket ventral to the epandrium (see below). Ratchet- 
like, the two gonapophyses together are worked down and in by the 
gonostyles. Finally each gonostyle becomes securely seated on the cor- 
responding gonapophysis, for its inner tooth (figs. iD; 2A, B) 5 
engages the lateral notch of the gonapophysis near its base (fig. iB, 
compare with iA and C, arrow). 
The female is then released from the clasp of the male’s wings. 
Thereupon she rocks backward 90° or more, with rostrum and an- 
tennae folded between the forelegs, femora drawn up to the sides, 
tibiae adducted, tarsi drooping — the “death-feigning” posture that 
concludes the leap of a startled Boreus. Surprisingly, the female 
thereafter remains vertically in that posture, though her legs relax, 
and the male folds his wings to their usual rest position over the back, 
fig. iA). In side view it can be seen that the tip of the aedeagus has 
been fully inserted into the common oviduct (fig. iC). Despite the 
unbalanced appearance of a male and female united thus at a right 
angle, without any noticeable difficulty the male may run, climb, 
feed, and hop, landing without loss of balance. If startled, the male 
may leap several centimeters or more, landing in (or assuming) the 
death-feigning posture, motionless and resting on his flank; the female 
too death-feigns as before; after a few moments, the male returns 
to his feet. 
In all, ten cases have been timed from the first assault of the male 
to intromission; these took from 6 minutes to 18, with a mean of 
13 minutes (all at i7°-20°C). The total duration of intromission 
has not been timed, but I have observed cases in which it was less 
than an hour, others of more than several hours. Both sexes mate 
repeatedly, with the same or different partners. 
°Esben-Petersen (1921) was unable to see this median tooth in specimens 
before him of B. brumalis and B. nivoriundus ; Lestage (1940) took the 
supposed absence of a median gonostylar tooth as presenting a cardinal 
character for Euboreus, a genus he erected for all American species. For 
discussion of Euboreus, see Cooper (1972). 
