350 
THE STUDY OF INSECTS. 
Family SATURNIID^: (Sat-ur-ni'i-dae). 
The Giant Silk-worms. 
The large size of the members of the Saturniidae, and the 
ease with which the cocoons of most of the species can be 
collected, render them well known to every beginner in the 
study of entomology. The family includes our largest lepi- 
dopterous insects; and all of the species known to us are 
above medium size. They are stout-bodied, hairy moths, 
with more or less sunken heads, and strong, wide wings. 
They may be distinguished from the Citheroniidae, some 
of which rival them in size, by the form of the antennae of 
the males, and by the fact that except in the lowest genus, 
Coloraduiy which is a rare insect from the far West, the 
hind wings are furnished 
ii^nij with only one inner vein. 
11X4 The adults fly at night, and 
are attracted by lights. 
The head is small and 
deeply sunken in the thorax; 
the antennas are either fili¬ 
form or pectinated in the 
females, but always pecti¬ 
nated in the males; and the 
pectinations extend to the 
tip. Where the antennae of 
both sexes are pectinated, 
the males can be distin¬ 
guished by the larger size of 
their antennae. The palpi 
are small, and the maxillae 
but little developed, often 
obsolete. 
The thorax is densely clothed with hair. The wings are 
broad, and are often furnished with transparent, window¬ 
like spots. The frenulum is wanting. The humeral angle 
Fig. 429.—Wings of Sarnia cccropia 
