24 HOW INSECTS ARE CLASSIFIED 
Mallophaga 
These are parasitic insects, commonly known as bird lice, although 
there are some species that infest domestic animals. 
The metamorphosis is incomplete. Eggs laid by the adult female 
hatch into minute creatures looking 
much like the mature insect. 
The members of this order are 
plainly adapted for their parasitic life. 
The body is flattened. There are no 
compound eyes. Wings are absent. 
The antenne are short and simple. 
The mouth parts are fitted for biting, 
and the food consists of the hairs or 
feathers of the host, or loose scales of 
dead skin. The Mallophaga never 
feed on the blood of their host, as do 
the members of the order Siphonaptera, 
me the fleas. 
Bates: ae ae rae About 2000 species have been de- 
inal. scribed. 
$ 
Odonata 
The adults in this order are the dragon flies, often called “ snake 
feeders ’’ or “ darning needles.”’ 
Metamorphosis is incomplete. The nymphs, which hatch from the 
eggs, are aquatic, spending their lives beneath the surface of ponds or 
streams, where they lead an active existence, capturing and devouring 
such other forms of animal life as come within their reach. The mouth 
parts of the nymph are peculiarly adapted to its needs, being pro- 
vided with a hinged lower lip which can be extended, and which bears 
hooks on its farther edge. By means of these the nymph is enabled to 
catch its prey unawares. 
The adults are large insects, and have two pairs of strong, narrow, 
