. Annals of applied biology. Biology, Economic; Biochemistry. 25-2 Ap2)le and Pear Sucker There were many larvae bred from beginning to end. But I had to replace those that died in the course of breeding. There are pecu- liarities of each instar by means of which the different instars can be distinguished. These peculiarities will be described Fig. 8. Fig. 9. III. Description of the Instars. {a) General description, (i) Colour. A larva of each stage passes through the same cycle, though it is growing bigger in size. It is bright yellow when it hatches out or has moulted. The colour gra
. Annals of applied biology. Biology, Economic; Biochemistry. 25-2 Ap2)le and Pear Sucker There were many larvae bred from beginning to end. But I had to replace those that died in the course of breeding. There are pecu- liarities of each instar by means of which the different instars can be distinguished. These peculiarities will be described Fig. 8. Fig. 9. III. Description of the Instars. {a) General description, (i) Colour. A larva of each stage passes through the same cycle, though it is growing bigger in size. It is bright yellow when it hatches out or has moulted. The colour gradually changes to yellow-brown, or in some cases distinctly reddish. This change in colour may be due to exposure to atmosphere. But there is a complete change of colour in the nymphal stage, when it becomes entirely green. The larva of the fourth instar changes its colour from brown to pale green as it matures for the fourth moult. (ii) Secretion (Fig. 10). The larvae of these insects are unmistake- ably recognised by their secretion. All the larvae, including the nymphs, have opaque white secretion, a long thread of which is hanging out from the hinder portion of the abdomen. This thread consists of a central core of translucent liquid covered externally by the whitish material which prevents its exuding and thus wetting the surface of a leaf. The larva begins to secrete as soon as it hatches out or has moulted. The thread in some cases reaches a great length; at the end there is a big knob- like swelling. If the thread is pricked, the translucent liquid exudes and wets the surface. This secretion is of a waxy nature and is soluble in alcohol. Besides this big thread issuing from the anus, there are small spine-like threads projecting from the extremity of the abdomen. They are shining and seem to change colour, which is not their intrinsic. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration
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