File:Zoological lectures delivered at the Royal Institution in the years 1806 and 1807 (1809) (14775424121).jpg

Identifier: zoologicallectur21809shaw (find matches)
Title: Zoological lectures delivered at the Royal Institution in the years 1806 and 1807
Year: 1809 (1800s)
Authors: Shaw, George, 1751-1813 Mearns, Edgar Alexander, 1856-1916, former owner. DSI Royal Institution of Great Britain
Subjects: Zoology
Publisher: London : Printed for George Kearsley, by Thomas Davison
Contributing Library: Smithsonian Libraries
Digitizing Sponsor: Biodiversity Heritage Library

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pierced with a vast number of holes througheach of which proceeds a distinct thread, and theanimal can either draw its thread from all theholes at once or by any particular number j inshort what we call a single spiders thrcjad mayconsist, according to some computists, of not lessthan six thousand distinct filaments. The size towhich the European spiders arrive is not verygreat, but the hotter regions of Africa and Ame-rica produce spiders of a size so gigantic as to befonuidable even to birds and many other animalson which they prey. One of the chief of these isthe Aranea Avicularia or Bird-catching Spider, ofwhich very capital specimens may bie seen in theLeverian Museum. These Spiders are foundprincipally in the hotter parts of South-America. The genus called Acarus or Mite contains thesmallest of all known Insects, as well as some ofconsiderable size. The mites are a very numerousrace. The generic character consists in havingeight legs, and in many species a kind of claspers. 123
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LECTURE IX. 119 operating as a pair of additional legs. The bodyis of a thick and roundish shape; in some speciesnearly globular, and in others flattish. The com-mon Cheese-Mite or Acarus Slro of Linnseus isa familiar example of the genus. It proceeds froman egg deposited by the parent insect, and is atits first hatching, perfectly like the parent exceptin size, and in wanting the third pair of legs,which do not make their appearance till after thefirst casting of its skin. Tlie Mite is beset withlong hairs, and if it be accurately surveyed bythe microscope, it will be found that these hairsare not of a simple structure, but are beardedalong the sides in the manner of the bristles onan ear of barley. To the genus Acariis or Mite belongs a verycurious Insect popularly known by the name ofthe Harvest Bug, which is of a bright scarletcolour, and so very small as to be but just visibleto a good eye without the assistance of a glass.In the middle of summer, or rather towardsits decline, th

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