File:Indian forest insects of economic importance. Coleoptera (1914) (14596465649).jpg

Identifier: indianforestinse00stebuoft (find matches)
Title: Indian forest insects of economic importance. Coleoptera
Year: 1914 (1910s)
Authors: Stebbing, Edward Percy, 1870-1960
Subjects: Beetles Forest insects -- India Trees -- Diseases and pests
Publisher: London Eyre & Spottiswoode
Contributing Library: Earth Sciences - University of Toronto
Digitizing Sponsor: MSN

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egg stage. The grubs on hatching tunnelaway from the egg-gallery in a direction which is more or less at rightangles to it in the case of those first hatching, and therefore the lowest eggs,the direction, however, trending upwards (or downwards when the egg-gallery is carried downwards) in the case of the eggs laid higher up thegallery. In this manner a pattern which has a constant definite planis made. The larval galleries are short, not being more than i£in. toi k in. in length, and they groove both bark and sapwood. When full-grown the larva eats out in the sapwood an oval-shaped depression, and 9003 K K 5M FAMILY SCOLYTIDAE changes into a pupa within this. Fig. 333 and pi. xlix show pieces of barkcompletely covered with the pairing-chambers, egg-galleries, larval galleries,and pupating-chambers. The pupa turns gradually into the immaturebeetle, and the latter remains for a time resting in the chamber whilstits outer parts are slowly hardening and it is becoming darker in colour.
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FlG- 333-—Egg and larval galleries of Jolygrap/nts trenchi, Steb., on inner bark of rinns gcranliana. North Zhob, 1905. /hen fully mature, the beetle bores straight out of the bark by a eaten out horizontally from the spot where it is lying. In the spring generation, when the weather is still comparatively as much as five weeks are probably spent in the larval stage and a FAMILY SCOLYTIDAE 515 fortnight in the pupal and immature beetle stages, the generation takingabout two months to complete from egg to perfect insect. It will beunderstood from the above that numbers of the beetles will mature andleave the tree together, and this is what actually happens, and explainsthe state of affairs seen in the second and fourth trees alluded to above.In the first and third the insects maturing were those from the firstset of eggs laid in the spring of 1905. In the second and fourth we findbeetles all more or less in the same stage, i.e. the egg-laying one (especiallyin the case of the second

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