IOO 
Psyche 
[March 
hand, the seven species of Panorpa so far reported upon by Naville 
and de Beaumont (1934), Kichijo (1943), Ullerich (1961), and 
Atchley and Jackson (1970) stand apart, having the highest chro- 
mosome numbers known for Mecoptera; they are: ncT = 20 + X, 0 , 
ncf =21 + X, 0 , and ncf — 22 + X ,0 (4 species, plus one with 
n? = 23). 
The cytology of Panorpa is thus characterized by two evolution- 
ary differences from most other Mecoptera now known: absence 
of chiasmata at meiosis in the male, as Ullerich (1961) first demon- 
strated, and unusually high diploid numbers. Whether or not male 
Nannochoristids and Choristids have chiasmata is not known, al- 
though Bush’s (1967) account indicates that male Nannochorista 
dipteroides , like Panorpids, may have a meiosis without chiasmata. 
Despite the strongly derived nature of the external morphology of 
Boreids, and especially of Boreus notoperates, therefore, their chro- 
mosome numbers and possession of chiasmata at meiosis in the male 
appear conservative. Congruent also with a primitive state is their 
possession of panoistic ovarioles, as is known also for B. hrumalis 
(Cooper 1940) and B. nivoriundus (unpubl.). It is likely that this 
is the case also for B. hy emails; Steiner (1937) could find no nurse 
cells in its ovaries, but was undecided as to whether the ovarioles 
are panoistic or meroistic. 
OviPOSITION 
As commented above, both male and female Boreus mate repeatedly 
and with varied partners. In B. notoperates the spermatheca of the 
female has some 24 sperm receptacles (fig. 9, Cooper 1972), all of 
which come to be filled with spermatozoa. The natural promiscuity 
may be seen as tending to reduce close inbreeding within the small, 
scattered populations. In the laboratory, females lay within two 
weeks following their first mating, and perhaps within a few days as 
is the case for B. hy emails (Striibing 1950, 1958). 
The large majority of the eggs at laying (which measure from 
0.5 to 0.6+ X 0.3 + mm, length by width) 10 by B. notoperates are 
placed singly, vertically, and ordinarily at such a depth that the apex 
of the egg lies from 0.1 to 0.3 mm below the surface of the sod of 
the moss, amid its rhizoids. Sixteen females, over a period of ten 
days at 2i°C, laid 186 eggs that I was able to locate — assuredly a 
10 The egg widths in Cooper (1972), p. 275, should of course be 0.31 mm 
and 0.30 mm respectively. 
