the Orders of Orthoptera and Neuroptera. 153 
great diversity in form from the Sialide to the Trichoptera. 
The mouth-parts are free, and the mandibles well developed, 
except in the Trichoptera, where the mandibles are nearly 
obsolete in form and functionless, thus suggesting or antici- 
pating the Lepidoptera. 
In the Neuroptera the ligula is entirely unlike that of any of 
the foregoing and lower groups. It is entire, forming a broad, 
flat, large rounded lobe; it is largest in Myrmeleon, Ascala- 
phus, and Mantispa, but smaller in Corydalis, where it is also 
narrower and indented on the front edge. 
In Panorpa the ligula is minute, rudimentary ; in the Tri- 
choptera it is also minute and rudimentary. 
The prothorax is usually (Planipennia) large, broad, and 
square, but is ring- or collar-like im the Trichoptera, being 
short and small, much as in Lepidoptera. Except in the 'T'ri- 
choptera, the meso- and metanotum are characterized by the 
large cordate preescutum; and in the Hemerobina the meta- 
scutum is partially or (in Ascalaphus) wholly cleft, the pre- 
scutum and scutellum meeting on the median line of the 
thorax. 
In the Hemerobina and Sialidez the metathorax is as large 
or nearly as large as the mesothorax, and the hind wings are 
as large as the anterior pair. The wings are not net-veined, 
the type of venation being entirely unlike that of the Ortho- 
ptera and Pseudoneureptera. The costal space is wide and 
well marked, and the transverse veinlets are few and far apart 
compared with the two orders just mentioned. 
The abdomen is cylindrical; and there are nine or ten uro- 
meres. The ovipositor is only developed in Rhaphidia, while 
the cercopoda are not developed. The metamorphosis is 
complete, as in the Lepidoptera &c., the pupa being entirely 
unlike the larva, and quiescent, often protected by a cocoon 
or case. The order may be divided into two suborders :— 
1. Planipennia (Sialide, Hemerobiide, Panorpide). 
2. Trichoptera (Phryganeide). 
The following tabular view will in a degree express our 
views as to the classification of the orders of the hexapodous 
or winged insects :— 
