Identifier: someinsectsinjur58unit (find matches)
Title: Some insects injurious to forests
Year: 1910 (1910s)
Authors: United States. Bureau of Entomology
Subjects: Trees Insect pests
Publisher: Washington, D.C. : U.S. Dept. of Agriculture, Bureau of Entomology
Contributing Library: U.S. Department of Agriculture, National Agricultural Library
Digitizing Sponsor: U.S. Department of Agriculture, National Agricultural Library

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the female they are much shorter than in the male, but are stillsomewhat longer than the body. Egg.—The egg (Hg. 15) is elongate-oval, approximately 4mm long.by 1.5mm in diameter at the middle. The color is opaque white.There are two distinct coverings, which correspond to the outer andinner shells of the egg of a fowl. The outer is known as the chorion(fig. 15, a, d), and the inner as the amnion (fig. 15, b). At one endis found a depression or little round hole, which is known as the micro-pyle (fig. 15, c). Under a high-power microscope the chorion is seento be very prettily sculptured on its outer surface (fig. 15, e). Larva.—The larva (fig. 16) is an elongate, footless, white grub withpowerful jaws or mandibles for boring through the wood. The sizevaries considerably in different individuals and according to age.The largest at maturity have been found to measure slightly over60mm in length and 9° in breadth at the broadest point (the pro- 46 SOME INSECTS INJURIOUS TO FOEESTS.
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Fig. 14.—The pine sawyer (Monohammus titillator): tf, Male;9, female. Enlarged about one-third. (Original.) THE SOUTHERN PINE SAWYER. 47 thorax). Larvae which develop into the smaller sized adults are, ofcourse, much smaller than this at maturity. The body is divided into 14 well-marked segments. The first is the head. The followingthree constitute the thorax, the first being the prothorax, the secondthe mesothorax, and the third the metathorax. The following 9ments constitute the abdomen, and are desig-nated as the 1st, 2d, 3d, etc., abdominal seg-ments. The last segment is called the analsegment. The head (fig. 16, a) is considerablylonger than broad, and is capable of beingdeeply retracted into the thorax. The pro-thorax, upon the anterior part of the upper ordorsal surface, is smooth and shining, but theposterior part has an opaque leathery appear-ance. This opaque surface is dotted over bysmall shining spots more or less longitudinallyelongate in shape. The mesothorax is smooth

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