264 
THE STUDY OF INSECTS. 
The characteristic features in the structure of the wings 
are the following (Fig. 311): the fore wings have a single 
anal vein, the hind 
wings two ; in both 
wings cubitus is 
apparently three- 
branched ; and the 
subcosta of the hind 
wings does not make 
a sharp bend into 
the humeral angle 
as it does in the 
Geometridae (Fig. 
323). In some 
forms the basal part 
of vein V is more or 
less distinctly pre¬ 
served ; and in some 
an accessory cell is 
present. 
The larvae feed 
Our most common 
species live exposed ; but some species live in folded 
leaves. They are either naked or thinly clothed with 
hairs. Many species have only four well-developed pro¬ 
legs, the anal pair being rudimentary, or transformed into 
elongated spikes. Some species are hump-backed; and 
spines or fleshy tubercles are often present. The trans¬ 
formations occur in slight cocoons or in the ground. 
The family is a large one, more than one hundred species 
occurring in the United States. The following are some of 
the more common species:— 
The Handmaid Moths, Datana (Da-ta'na).—Among the 
more common representatives of the Notodontidae are cer¬ 
tain brown moths that have the fore wings crossed with 
bars of a different shade (Fig. 312) and that bear on the 
Fig. 311.—Wings of Notodonta stragula. 
upon the leaves of shrubs and trees. 
