152. Dr. A. 8. Packard, Jun., on the Classification of 
the notum of meso- and metathorax, though of the same type 
as in the Orthoptera, is minute in size. The prothorax is very 
small, both dorsally and on the sides forming a collar. 
The wings are as markedly net-veined as in the Ortho- 
ptera, though the hinder pair are not folded longitudinally as 
in that order. The Odonata literally live on the wing, and 
thus the shape of the sclerites of the notum of the wing-bear- 
ing segments approaches that of the Orthoptera, although the 
prothorax is remarkably small compared with that of the 
Orthoptera, and forbids their union with this order, as was 
done by Gerstiicker and other German entomologists. The 
head of the Odonata is remarkable for the enormous size of 
the eyes and the consequent great reduction in size of the 
epicranium as compared with the large epicranium of the 
Orthoptera. The mouth-parts are like those of the Ortho- 
ptera, except that the second maxille form a remarkable 
mask-like labium. The abdomen is very long, slender, and 
cylindrical; there are eleven uromeres, the eleventh being 
well represented, while the cercopoda are not jointed, but in the 
form of claspers. 
3. Ephemerina.—In the small epicranium and the large 
male eyes the Ephemerina resemble the Odonata, though the 
rudimentary mouth-parts are in plan entirely unlike theirs. 
So also the prothorax is small and annular ; but the subspheri- 
cal concentrated thorax is remarkable for the large meso- 
thorax and the small metathorax. Hence the hind wings are 
small and sometimes obsolete. The long slender abdomen 
has ten uromeres, and bears, besides the two long filamental 
multiarticulate cercopoda, a third median one. 
The larvee of the lower Odonata and of the Ephemeride 
closely approach in form those of the Perlide, showing that 
the three suborders here mentioned probably had a common 
ancestry, which can be theoretically traced to a form not 
remote from Campodea. By reason of the general resem- 
blance of the larval forms of these three suborders it would be 
unadvisable to separate the Odonata and Ephemerina from 
the Platyptera, although when we consider the adult forms 
alone there would appear to be some grounds for such a 
division. 
Order 4. NEUROPTERA. 
The head is horizontal and somewhat flattened, except in 
the Trichoptera and Panorpide, where it is subspherical and 
vertical. ‘The body shows a tendency to be round or cylin- 
drical, the thorax being more or less spherical ; but there is 
