. Annals of applied biology. Biology, Economic; Biochemistry. 150 Knapweed Gall-flu The first segment of the ovipositor (which appears as the terminal segment of the abdomen) is about 2'7 mm. long ; it is swollen anteriorly, being about 0'6 mm. across in this region, and it becomes narrower in the posterior portion ; near the distal end it is about 0-25 mm. in diameter. The w^alls are strongly chitinised and it is covered with numerous hairs. The second or middle segment of the ovipositor is about 2-3 mm. in length, by 0-15 mm. wdde along its whole length, and consists of a transparent flexibl
. Annals of applied biology. Biology, Economic; Biochemistry. 150 Knapweed Gall-flu The first segment of the ovipositor (which appears as the terminal segment of the abdomen) is about 2'7 mm. long ; it is swollen anteriorly, being about 0'6 mm. across in this region, and it becomes narrower in the posterior portion ; near the distal end it is about 0-25 mm. in diameter. The w^alls are strongly chitinised and it is covered with numerous hairs. The second or middle segment of the ovipositor is about 2-3 mm. in length, by 0-15 mm. wdde along its whole length, and consists of a transparent flexible membrane in which a great number of small chitinous sclerites are partially embedded. This segment is capable of protrusion and retraction, like the finger of a -•.?<; Fig. 1. Extended ovipositor of U. solstitialis from left side, x 15. 1, 1st segment of the ovipositor ; 2, 2nd, flexible segment; 3, 3rd, piercing segment The third and last segment is the actual piercing portion of the ovipositor ; it is composed of chitin, is about 2-3 mm. long, and except at the extreme narrow tip is about 0-07 mm. in diameter. There are two sharp-cutting blades at the sides of the tip. This segment contains the terminal portion of the oviduct, which opens to the exterior near the tip. During the passage of the ova this segment probably expands slightly. The ovipositor is extended by pressure, presumably by muscular compression acting on some of the body-fluids. If the swollen portion of the ovipositor is compressed with a pair of forceps, the flexible and piercing segments are readily everted, and they always assume a curved. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Association of Applied Biologists; Association of Economic Biologists. [Wellesbourne, Warwick, etc. ] Association of Applied Biologists [
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