. The pear thrips (Euthrips pyri). Pear thrips. 10 THE PEAR THRIPS. ally heavy driving rains, and we were unable in many cases to deter- mine the amount of injury done by the thrips and the amount caused by the rain, except in those places where injury done by the insects was noticed before the rains came on. The damage, however, will aggregate many thousands of dollars. LIPE-HISTORY AND HABITS. The Egg, the Ovipositor, and the Placing of the Egg.—The egg is bean- shaped, is almost transparent, and when seen within the body of the adult female is very large in proportion to the size of the abd
. The pear thrips (Euthrips pyri). Pear thrips. 10 THE PEAR THRIPS. ally heavy driving rains, and we were unable in many cases to deter- mine the amount of injury done by the thrips and the amount caused by the rain, except in those places where injury done by the insects was noticed before the rains came on. The damage, however, will aggregate many thousands of dollars. LIPE-HISTORY AND HABITS. The Egg, the Ovipositor, and the Placing of the Egg.—The egg is bean- shaped, is almost transparent, and when seen within the body of the adult female is very large in proportion to the size of the abdomen. It can be seen only with a powerful lens or microscope. The ovipositor—the organ fitted for cutting an incision in the plant tissue and for convey- ing eggs from the abdomen of the adult female into this incision—is made up of four distinct ^'"of' thr'ips"'sholiu|'"ovi- plates, each of which has a serrate outer edge, positor, greatly enlarged, is pointed, and is Operated by powerful muscles and plates within the abdomen. (See Fig. 5.) -^ In placing an egg, the thrips first tears or weakens the plant epi- dermis by means of the mouth parts, takes a step forward, and, arching the abdomen a little, lowers the ovipositor from its sheath in the last two abdominal segments, almost at right angles with the body, and by operating the tiny saws up and down, she enlarges the opening and cuts a quite deep incision. When this is finished an egg is forced down through the space between the four plates and into the cavity below, underneath the plant epidermis. The operation of making the incision, of depositing a single egg, and of withdrawing the ovipositor requires from four to ten minutes, and has been observed many times. One often finds a branch or a whole tree where almost every female will be depositing eggs at the same time. For depositing eggs, the tiny and very tender stems of blossoms and leaf petioles are preferred, and as the leaves develop the midrib
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Keywords: ., bookcentury1900, bookcollectionbiod, bookdecade1900, bookyear1905
