. Annals of applied biology. Biology, Economic; Biochemistry. Walter Ritchie 331 hole appears only as a longitudinal crack on the surface of the bark. Usually the exit hole occurs about four to six inches above the level of the ground but in a few cases it was cut well up the stem, occurring as high as one and a half feet. As a rule this portion of the gallery is not completed all at once, but the larva returns again and again from the centre of the stem until it is completed. On the completion of this portion of the gallery the larva plugs it tightly with gnawed material. (d) The pwpal portio
. Annals of applied biology. Biology, Economic; Biochemistry. Walter Ritchie 331 hole appears only as a longitudinal crack on the surface of the bark. Usually the exit hole occurs about four to six inches above the level of the ground but in a few cases it was cut well up the stem, occurring as high as one and a half feet. As a rule this portion of the gallery is not completed all at once, but the larva returns again and again from the centre of the stem until it is completed. On the completion of this portion of the gallery the larva plugs it tightly with gnawed material. (d) The pwpal portion. The larva now continues to bore up the centre of the stem in the vertical direction and may reach a height of 1 ft. 9 in. or 2 ft. in the centre of the stem. By this time it is full grown and is ready for pupation. Enlarging slightly the diameter of the portion of the tunnel just cut, K ffl, » i ullfl'iM',., WWW. Fig. 25 a. Portion of stem of a 12 year old poplar showing oval exit hole made by larva for exit of adult. Fig. 25 b. The same in transverse section to show the complete exit portion of gallery. the uppermost portion, it seals the burrow tightly behind it with a dense plug of coarse frass ripped roughly from the side of the gallery. This operation being completed, the larva now within its pupal bed, ceases to feed, reverses its position, its head-end resting on the plug of frass at the lower end of the cell, shrinks slightly, moults, and the pupa is revealed. The moulted chitinous head parts of the larva are found lying in the upper end of the pupal chamber. The length of the pupal chamber is on an average 1-| inches. The time taken by the larva for the completion of the whole gallery, excluding the hibernating period, is about eight and a half months. After the period of pupation has passed, the young imago bores through the plug of frass at the base of the pupal chamber, and then. Please note that these images are extracted from scanned page images that
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Keywords: ., bookcentury1900, bookdecade1920, booksubjectbiochem, bookyear1921
