INSECT ENEMIES OF EASTERN FORESTS 63 
THE SPIDERS 
Orpver ARACHNIDA 
The spiders are merely mentioned here to show their relationship 
to insects in the general scheme of classification. Their predatory 
habits, chiefly on sects, cause them to rank as highly beneficial and 
useful. The black widow spider and the tarantulas, which are pro- 
vided with poison saes, occasionally bite men, causing painful, though 
rarely fatal, wounds. The spiders and their relatives are adequately 
treated by Comstock (104). 
THE HARVESTMEN 
Orpver PHALANGIDA 
The harvestmen, or daddy-long-legs, are fairly well characterized 
by the latter name. They have a small, compact, nearly elobular body 
supported by eight long angular legs on which they awkwardly totter 
about. They are of no economic importance, as they feed on dead 
insects and vegetable matter, but they frequently attract attention 
around houses and camps. 
THE MITES, TICKS, AND RED SPIDERS 
Orper ACARINA 
The acarinids are of considerable economic importance in the forest 
to plants, wild game, and to man, as well as in their relation to agri- 
culture. For a very good general treatment of western forms see 
Essig (745). Several families will be discussed separately to better 
bring out their importance. Several species of mites representing 
different families are very abundant under the bark of trees that have 
been killed by bark beetles. These are predaceous and reasonably 
beneficial in destroying bark beetle eggs. 
THE ITCH MITES 
Famity SARCOPTIDAE 
One of the representatives of the itch mite group is the common 
itch mite (Sarcoptes scabici Deg.), which attacks man and canses the 
skin disease known as itch or scabies. Related species cause mange 
of domesticated animals. Sulfur ointments; tar oil; nicotine solu- 
tions; and, in persistent cases on dogs, a 10-percent silver nitrate solu- 
tion, have been used effectively. Derris or cube used as an oimtment 
or wash is especially effective. 
A related form, the chicken mite (Dermanyssus gallinae (Deg.)), 
is a serious pest of poultry and attacks game birds as well, particularly 
while they are in confinement at breeding stations. This pest can be 
controlled by spraying the pens with kerosene. If the birds can be 
kept out of the pens for 24 hours anthracene oil may be used. ‘This 
latter material is very effective and persistent. 
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