CHAPTER II 
Tue Parts or AN InsEct’s Bopy 
The Head 
ADULT insects have a more or less distinct head, varying greatly in 
shape according to the habits of the species. 
Prominent on either side, near the top of the head, are usually to be 
seen the compound eyes. These 
are very large in some groups, 
such as the horseflies or dragon 
flies, which need to have espe- 
cially good vision, but are absent 
in some other groups, such as 
certain parasites, which have little 
need of the ability to see. A com- 
pound eye is made up of many 
lenses, each with its own sensi- 
tive area and nerve. The num- 
ber of these lenses often is great; 
the common house fly has about Fic. 4.— Head of a beetle, showing 
4000 on each side. mouth parts. Enlarged and natural 
size. Original. 
Between or above the compound 
eyes are usually three simple eyes. These are small, but can be made 
out readily by looking closely. 
Near the compound eyes are the antenne, or “feelers.”” Their 
shape is diverse with the different groups, and is one of the valuable 
means of determining the identity of many insects, or of placing a 
specimen in its proper group. Eight or ten general types of antenne 
are recognized. 
