710 REVIEWS. 
Orthopterous, or Pseudoneuropterous, we would abide by embryo- 
logical data to decide the question. The embryology of the Libel- 
lulide is perhaps as thoroughly known as that of any other 
group of insects. During the past summer the writer has observed 
with considerable care the embryology of Chrysopa, a type of the 
“true” Neuroptera, in the restricted sense. In the earliest and 
later stages the development of this genus is almost identical with 
that of the dragon flies, as regards the structure and relations of 
the ‘“‘ammion” and ‘visceral membrane,” the relations of the 
primitive band, the early form of the embryo, and its position 
just previous to exclusion from the egg (see this journal, p. 564). 
The differences are merely such as we would expect to find be- 
tween two families of the same order. Thus embryology gives 
us the most unexpected and independent testimony as to the 
close alliance at least of the Libellulidze and Hemerobide. Should 
our conclusions stand the test of the observations and criticisms 
of abler naturalists, then have we not demonstrated the close re- 
lationship of these two divisions of (what we regard as) Neurop- 
tera? We conceive the greatest gap in the Neuroptera (in the 
Linnzan sense) to be between these two families. The Libelluli- 
dæ, through the Ephemeride, their nearest allies, pass into the 
Perlidz and Psocide ; on the other hand, the Hemerobide are con- 
nected by many characters with the Panorpide, and to the latter, 
as we believe, the Phryganeidæ (Trichoptera) are more nearly 
related than any other group of insects, whether we take into con- 
sideration the structure of the adults, or the form of the larva 
and pupa, and their metamorphoses. The gap between the Libel- 
lulidze and Hemerobide is indeed a wide one, but have we not 
seen that the foundations of the bridge have been laid in the em- 
bryonic stages, and may we not feel authorized in view of recent 
discoveries of paleozoic net-veined insects, in believing that the 
superstructure, the arches and timbers of the bridge, has been 
swept away by the storms and floods of past geologic ages! ? Evi- 
dence is accumulating and growing stronger each year, if we in- 
terpret the facts aright, that the gaps between what we consider 
the families of the Neuroptera are due to the extinction of genera 
and species in paleozoic and mesozoie times. So that instead of 
a “dismemberment” of the Neuroptera, we shall really have å 
more thoroughly compacted and natural group than as yet recog- 
nized by systematists. 
