Image from page 105 of "Introduction to zoology; a guide to the study of animals, for the use of secondary schools;" (1900) (14761987916)

Identifier: introductiontozo00dave

Title: Introduction to zoology; a guide to the study of animals, for the use of secondary schools;

Year: 1900 (1900s)

Authors: Davenport, Charles Benedict, 1866-1944 Davenport, Gertrude Anna Crotty, 1866-

Subjects: Zoology

Publisher: New York, Macmillan company London, Macmillian and co., ltd.

Contributing Library: MBLWHOI Library

Digitizing Sponsor: MBLWHOI Library

Text Appearing Before Image:

FIG. 82. — Mygale, a Tunnel-weaver, allied to the trap-door spider. Nat. size. From Emerton. 1. Tunnel-weavers (Territelarite 1). These spiders maketubes in the earth, and line them with silk. The repre-sentatives of this group in the Southwestern States are 1 terra, earth ; tela, tissue or web. 86 ZOOLOGY

Text Appearing After Image:

commonly known as trap-door spiders. The lid of thenest is covered with hardened dirt, and when closed, looks exactly like the ground around FG it. Some of these spiders gain a great size and capture birds(Fig. 82). 2. Orb-weavers (Orbite-lariee1). These, which aretypically represented byArgiope, are well known; yetfew persons have studied thealmost mathematical precisionwith which the webs are built.Foundation lines (Fig. 83)of unusual strength are firstlaid down, to form the periph-ery or frame of the web. Thenradii are spun from a centrallittle ball of floss to the frame. The radii are, often atleast, laid down alternately on opposite sides of thecentre. The number of radii formed by a species ofspider is not perfectly constant, but varies within limits.It would be an interesting occupation to sketch a numberof webs of Argiope showing the variations in the numberof radii and the other details of form. After the radii areplaced, the spiral lines are laid down. In the completedweb fo

illustrations of spider webs introduction to zoology a guide to the study of animals for the use of secondary schools book illustrations ornithology birds zoological illustration zoology images from internet archive

1944

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