EMBRYOLOGY OF CHRYSOPA. 565 
in the Libellulide, but the head remains throughout embryonic life 
next the micropyle. At the next stage observed, the appendages 
of the limbs had appeared, the embryo being situated on the out- 
side of the yolk, the end of the abdomen curved around on the 
opposite side of the yolk. At this time the inner or “ visceral 
layer,” forming a second moult of the blastoderm, envelops the 
germ, much as in the Libellulide, and Hemiptera, and Coleoptera 
(Donacia). It is evident that this faltenblatt of Weismann (or 
visceral layer of Brandt) is shed at a later stage than the “‘ amni- 
on” proper. This stage corresponds with that of Calopteryx 
figured by Brandt (Pl. 1. fig. 11). At this time the germ of 
Diplax and Calopteryx (Libellulidee) floats within the yolk, but 
this ‘difference I would regard as having no special importance, as 
in the Hemiptera the germ at the same stage of development rests 
on the outside of the yolk in Corixa, while in the Pediculina, 
according to Melnikow’s researches, the germ floats within the 
yolk, and we shall see farther on that in the Curculionide (Attela- 
bus) the germ rests on the outside of the yolk (ectoblast), while 
that of Telephorus is a decided endoblast, 7. e., floats in the inte- 
rior of the yolk. After this period, the embryo of Chrysopa 
exactly corresponds to that of all the Libellulidse whose develop- 
ment is known (Agrion, Calopteryx, Perithemis, and Diplax.) 
embryogeny of Chrysopa is identical, then, with that of the 
Libellulide. What becomes, therefore, of the distinction between 
‘** Pseudoneuroptera” and “true” Neuroptera, insisted on by 
some of the leading entomologists, since Erichson’s day? Never 
believing that the differences were great enough to Separate the 
innzan Neuroptera into two independent orders or suborders 
(whichever we may choose to call them), I now ask if embryology 
does not give independent testimony as to the close alliance at 
least of the Libellulide and Hemerobidve, even if we go no farther? 
The only Coleoptera with whose development we are acquainted 
is Donacia, worked out more carefully by Melnikow than any one 
else. During this summer I have studied Telephorus fraxini and 
Attelabus rhois in nearly all their embryonic stages. They are 
developed in the same manner as in Donacia. There is a parietal 
(‘amnion’) and a visceral membrane in Attelabus; (it was not 
observed in Telephorus, though it doubtless exists), as in Donacia. 
In Attelabus, however, the primitive band rests on the outside of 
the yolk, while in Telephorus it floats in the yolk, and farms a 
