Acalitus phloeococotes (Nalepa) detorms fruit spurs and produces woody galls on 
plum. Nalepella tsugifoliae Keifer has been reported to damage hemlock in nurser- 
ies in New York. The pine bud mite, 7risetacus pini (Nalepa), causes the yellowing 
and dropping of pine needles. 7. cupressi (Keifer) attacks southern redcedars, 
causing distortion and deformation of young trees. 
F-506694 
Figure 10.—Galls of the maple bladdergall mite, 
Vasates quadripedes, on leaf of mapie. 
Mites of the family Sarcoptidae are skin parasites of warm-blooded animals. The 
itch mite, Sarcoptes scabiei (De Geer), is a well-known species. It attacks humans 
and causes severe itching as it burrows into the skin. 
The family Trombiculidae contains the notorious redbugs or chiggers. The 
common chigger in the Eastern United States is the first instar of the species, 
Eutrombicula alfreddugesi (Oudemans). In its later stages, it feeds on insects, 
snakes, birds, lizards, and rodents. When it attaches itself to the skin of humans and 
insects, it inserts its mouth parts to feed, causing intense itching and sores. Heavy 
attacks may cause fever, and secondary infections may occur. Chiggers are often 
abundant in the forests of the Central and Southern States and along the Atlantic 
seaboard north to New Jersey. 
Many other species of mites occur in association with bark beetles (89/), and 
some are known to be parasitic. So far, very little information is available on their 
effectiveness in natural control of the beetles. In some instances, it may be 
substantial. 
Ticks.—Ticks are all parasitic, chiefly on mammals, birds, and reptiles. All 
American species have a number of features in common, such as large size, a 
piercing hypostome with recurved teeth, and chelicera with lateral teeth on the 
movable digits. Some ticks are mostly covered by a hard dorsal plate called the 
scutum; in others, this hard plate is absent. 
The American dog tick, Dermacentor variabilis (Say), occurs throughout the 
Eastern United States, but is most abundant in coastal areas and in the Mississipp1 
River Valley. The larvae and nymphs feed largely on rodents; the adults feed on 
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