A text-book of entomology, including the anatomy, physiology, embryology and metamorphoses of insects, for use in agricultural and technical schools and colleges as well as by the working entomologist . styles of the lowest or innermost pair, andunder the cross-bars or at the base of the stylets mentioned; thestyles or blades spreading apart to allow of the passage of the egg. The ovipositor is best developed in the Thysanura (Fig. 179, Cam-podea excepted), in Orthoptera (Fig. 184), in the Odonata, Hemiptera,certain P h y s a p o d a,Rhaphiidse, and in thephytophagous Hymen-optera, where it is
A text-book of entomology, including the anatomy, physiology, embryology and metamorphoses of insects, for use in agricultural and technical schools and colleges as well as by the working entomologist . styles of the lowest or innermost pair, andunder the cross-bars or at the base of the stylets mentioned; thestyles or blades spreading apart to allow of the passage of the egg. The ovipositor is best developed in the Thysanura (Fig. 179, Cam-podea excepted), in Orthoptera (Fig. 184), in the Odonata, Hemiptera,certain P h y s a p o d a,Rhaphiidse, and in thephytophagous Hymen-optera, where it is curi-ously modified to forma rather complicatedsaw for cutting slits inwood or leaves (). It is wanting orquite imperfect inColeoptera, Diptera,and Lepidoptera. Morphologically, the ovipositor appears to be formed out of theabdominal appendages of the seventh, eighth, and ninth segments ofthe female, which, instead of disappearing in the orders first men-tioned, persist as permanent styles. Wheeler asserts from his study of the embryonic development ofXiphidium there can be no doubt concerning the direct continuityof the embryonic appendages with the gonapophyses. He goes onto say : —. FIG. 185.— Saw of Ilylotoma : <i, lateral scale; i, saw;/,g-orget; ~(t. 7th tergite ; 6s, 6th sternite ; oi\ oviduct; in, intes-tine. — After Lacaze-Duthiers. 168 TEXT-BOOK OF ENTOMOLOGY One embryo, which had just completed katatrepis, still showed traces of allthe abdominal appendages. The pairs on the eighth, ninth, and tenth segmentswere somewhat enlarged. In immediately succeeding stages the appendages ofthe second to sixth segments disappear ; the pair on the seventh disappear some-what later. Up to the time of hatching the gonapophyses could be continuouslytraced, since in Xiphidiurn there is no flexure of the abdomen, as in otherforms, to obscure the ventral view of the terminal segments. From the timeof hatching Dewitz has traced the development of the ovipositor in anoth
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Keywords: ., bookcentury1800, bookdecade1890, bookpublishe, booksubjectinsects
