. The Acarina or mites. A review of the group for the use of economic entomologists. Mites. THE ACARIXA OR MITES. 137. 3. End piece of abdomen plainly separated Anthocoptes. End piece of abdomen not plainly separated Phyllocoples. 4. Some of the dorsal abdominal rings extend backward spinelike on the side OxypleuTites. Dorsal rings not so , 5 5. Dorsum of abdomen with two longitudinal furrows Epitrimerus. Dorsum without furrows Tegonotus. Most of the species, so far known from the United States, have been referred to Eriophyes, but several of the other genera occur here. The most notable of al
. The Acarina or mites. A review of the group for the use of economic entomologists. Mites. THE ACARIXA OR MITES. 137. 3. End piece of abdomen plainly separated Anthocoptes. End piece of abdomen not plainly separated Phyllocoples. 4. Some of the dorsal abdominal rings extend backward spinelike on the side OxypleuTites. Dorsal rings not so , 5 5. Dorsum of abdomen with two longitudinal furrows Epitrimerus. Dorsum without furrows Tegonotus. Most of the species, so far known from the United States, have been referred to Eriophyes, but several of the other genera occur here. The most notable of all our species is the pear-leaf blister mite, Eriophyes pyri Pagen- stecher, an European species whose introduction into this country seems to have been accomplished before 1870. It is now widely distributed throughout the pear-growing re- gion, and also occurs in Australia. It appears to be more injurious in this country than in Europe, and in some cases it is so abundant that the tree sheds nearly all its leaves before the fruit is ripe. The mites pass the winter in the buds, and begin to feed before the leaves are un- rolled. They form red blister like spots nearly one-fourth inch across. These spots become green by June, and then turn brown, and the tissue becomes hard and corky. The opening is on the under side. As mites often start galls close together, they soon coalesce and form large blotches. Prof. Slingerland has found that they can be practically exterminated by spraying the trees in winter with kerosene emulsion diluted with from 5 to 7 parts of water. This mixture reaches the hibernating mites in the buds and kills them there. The pear-leaf blister mite also occurs on apple leaves. The galls often contain other species of mites, three of which, Phyllocoptes schlechtendali Nalepa, Epitrimerus piri Nalepa, and Erio- phyes malifoliae Parrott, have been found in these galls in our country. Another species of considerable economic importance is Phyllocoptes oleivorus As
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