160 ENTOMOLOGY 
quite fantastic. 
in Fig. 207. As regards size, mo 
eres 
guises 
Aue 
ut 
UV 
UT 
(? 
f litte 
(UT 
UP 
(/ 
LR 
Mt 
IW 
WW 
Ut 
(UC 
tt 
(US 
Li 
[ 
mr 
=S== iS 
====—s=: 
S==5 Se 
=sS=s SSS 
===S en === 
Ea Se 
Three 
rape. 
scale. 
eggs of the cabbage butterfly, Pieris 
Greatly magnified, but all drawn to same 
= 
re) 
The egg-shell, or chorion, secreted 
arcund the ovum by cells of the ovarian 
follicle, may be smooth but is usually 
sculptured, frequently with 
which, as in lepidopterous 
serve to 
on the other hand, are as long as 
ridges 
eggs, may 
the =suell ine 
ornamentation of the egg-shell is often 
exquisitely beautiful, though the par- 
ticular patterns displayed are probably 
of no use, being incidentally produced 
as impressions from the cells which 
secrete the chorion. Variations of 
form, size and pattern are frequent in 
eggs of the same species, as appears in 
Fig. 208. 
Always the chorion is penetrated by 
one or more openings, constituting the 
mucropyle, for the entrance of sperma- 
tozoa. 
strengthen 
Something of the variety of form is shown 
st insect eggs can be 
distinguished by the 
naked eye; many oft 
them tax the vision, 
however, for example, 
the elliptical 
Cecidomyia  legumin- 
cola, which are but 
300 mm. in length 
and .075 mm. 1 
width; the oval eggs 
of the cecropia moth, 
eges of 
in 
mim. 
Fic. 209. 
Chrysopa, laying eggs. 
Slightly enlarged. 
As a rule, the eggs when laid are accompanied by a fluid of 
some sort, which is secreted usually 
glands, opening into the vagina. 
by a cement gland or 
This fluid commonly serves 
