Report of the State Entomologist on the noxious and beneficial insects of the state of Illinois . of the bur-oak, Qaercus macrocarpa,Michx. The mite is long and slender, and in a specimen seen amongwashings from a cecidium, there appeared to be an abrupt descentin the outline of the back from the abdomen to the .005 inch. The gall is large, greenish-yellow, entirely open below and slightlyconvex above. The hollow is densely filled with brown form is variable but the outline usually regular. The surfaceis smooth, or slightly roughened by the veinlets. Some of
Report of the State Entomologist on the noxious and beneficial insects of the state of Illinois . of the bur-oak, Qaercus macrocarpa,Michx. The mite is long and slender, and in a specimen seen amongwashings from a cecidium, there appeared to be an abrupt descentin the outline of the back from the abdomen to the .005 inch. The gall is large, greenish-yellow, entirely open below and slightlyconvex above. The hollow is densely filled with brown form is variable but the outline usually regular. The surfaceis smooth, or slightly roughened by the veinlets. Some of thesegalls grow downward instead of upward and form brown velvety but-tons on the under side of the leaves. Specimens measured werefrom .1 inch to .4 inch in diameter. Thirty galls have been countedon one leaf. This is a common gall in Northern Illinois and Indi-ana, and has been found occasionally in the central part of Illinois. Phytoptus thuja, n. sp. Occurs on the leaves of the American arbor vitae, Thuja occident-alis, Linn, in summer, and in the buds and under the leaves inwinter, 139. —PJiytoptus (ventral view.) a. rostrum;h, labium; c, cheliceree: d, appearance of jointsseen on the rostrum: e, tarsal claw; /, feather-like tarsal appendage; g. one of the first pair ofhairs on under sidt* of cephalothoax; h, one ofthe second pair of hairs on the under side ofcephalothorax; /, genital plate: j, abdominalsucker. 140 Adults of this mite measure from .005 to .0065 inch in length,with the greatest transverse diameter about .002 inch. They arewhitish and semi-transparent. Of the three pairs of hairs attachedto the dorsal surface, the first pair is attached at the posterior mar-gin of the cephalothorax, the second between the last two abdominalstriae just before the terminal sucker, and between the hairs of thispair is the third pair, consisting of two short and straight hairs of the second pair are abruptly bent at about the fourthof their length from the atta
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Keywords: ., bookcentury1800, bookdecade1870, booksubjectbenefic, bookyear1876
