412 LAURA FLORENCE 
so that a fork is formed, between the prongs of which are transverse 
ridges (Plate LX VI, 28). These structures have no very regular character, 
and Gross could not determine whether they originated as separate rings 
or as lamellae. In the vicinity of the furrow between the egg and the 
operculum the appearance is distinctly modified (Plate LX VI, 27, b). Here 
the branches of the network are themselves forked and their prongs are 
extended as longitudinal rings; also, the transverse rings are more numerous 
and irregular. Behind the operculum there is still another structure. 
Over the network of the exochorion, and at first without any connection 
with it, is formed a characteristic trellis of longitudinal and transverse 
rings, having as a groundwork a narrow, undulating band whose curved 
edges lie always on a furrow of the epichorion. The whole is then set 
through with transverse parallel rings, some of which are found also between 
the epichorion network. Directly behind the opercular furrow the chorion 
extends as two specially large projections which bend forward and are 
forked at their outer ends (Plate XLVI, 27, a). These are two lamellae, 
which extend around the whole circumference of the egg, overarching 
the furrow and protecting it. In the fully developed egg (Plate LX VI, 29) 
the rings are said to be made of chitin and to have become a part of the 
chorion. The remainder of the epithelium is now an amorphous mass 
and is the so-called egg-white layer around the egg, of which Gross says 
(page 370 of reference cited): ‘‘ Auch dieser Umstand, dass der Follikel 
schliesslich sich zur Eiweisshiille umbildet, ist, soviel ich weiss, ohne 
Analogon unter den Insecten.”’ The epichorion is connected with the 
exochorion anteriorly at the opercular ridge and posteriorly at the egg 
stigma,.a complicated structure whose significance is not clear. A diffusion 
of air through the pores cannot take place because of the egg white. 
An interchange of gas cannot take place, although the space between 
the exochorion and the epichorion contains a quantity of gas; rather is 
this chamber of gas to be regarded as a warm covering for the egg, or it 
may serve as a protection against injury from blows to which eggs attached 
to the hair of animals are exposed. 
In the egg of the hog louse the micropyles are not indicated by any 
special formation. In sections they can be seen as simple canals, narrowing 
somewhat at their inner ends, in the vicinity of the operculum. -Leuckart 
(1855:141) did not state their number; according to Gross (1906:371) 
there are at least thirty. 
