INSECTS AND THEIR NEAR RELATIVES . 
43 
transverse, fine lines, which are so impressed as to appear 
like the divisions between minute segments (Fig. 52). The 
majority of mites are very small; but some, as certain Ticks, 
are of considerable size. 
With the exception of a single family the members of 
which bring forth living young, all mites are produced from 
eggs. As a rule, the newly-hatched mites have only three 
pairs of legs; but a fourth pair are added during growth. 
In Phytoptus , which infests plants, there arc only two pairs 
of legs. 
The mode of life of the different members of this order 
varies greatly: some are parasitic upon animals; others 
infest living plants ; and many feed upon dead animal or 
vegetable matter, thus acting as scavengers. 
Among the mites that are parasitic upon animals are the 
various Ticks, which are very common in the 
warmer parts of our country. Figure 50 rep¬ 
resents the Cattle-tick of the Southern States. 
It should be remembered in this connection 
that the so-called Sheep-tick is a true insect, 
belonging to the order Diptera. 
The Itch-mite is a well-known parasite, infesting man 
and causing the disease known as 
the itch. The sensation character¬ 
istic of this disease is due to the 
burrowing of the mites in the skin ; 
and the efficiency of sulphur oint¬ 
ment in checking this disease is 
due to the fact that by the use of 
Figure 51 represents an itch-mite 
\ 
Parasitic mites are frequently found attached to insects ; 
a common species occurs beneath the wings of locusts. 
The best known of the mites that infest plants is the one 
commonly called the Red Spider. This lives upon house- 
plants ; and in the warmer parts of the country, where there 
Fig. 50. — The 
Cattle-tick, fe¬ 
male. 
Fig. 51. — An 
below ; 
Itch-mite: a, 
b. from above. 
from 
it the mites are killed, 
greatly enlarged. 
