390 CHARACTERS OF INVERTEBRATE ANIMALS 



Order 5. — Harvestmen (Phalangidae) 



Harvestmen constitute a large and almost universally-distri- 

 buted order, represented in this country by some two dozen 

 species. They are common in our fields and are generally mis- 

 taken for spiders, from which, however, the native species can 

 at once be distinguished by the great length and slenderness of 



the four pairs of legs, 

 and the fact that the 

 small oval body is not 

 marked off distinctly 

 into regions. The 

 chelicerse are provided 

 with relatively large 

 pincers, but the pedi- 

 palps are usually short 



Fig. 238. — A Karfestmaii {P/uiiangi7im o^lio) ■*■ ^ - -._ ,_,^ 



and leg - like. 1 he 

 breathing organs are air-tubes which open by a pair of stigmata 

 on a forward prolongation of the abdomen, just behind the bases 

 of the first legs. A pair of simple eyes is borne on the upper 

 surface of the cephalo-thorax. Phalangium opilio is one of the 

 commonest native species (fig. 238). 



Order 6. — Spiders (Araneidae) 



Spiders make up a very large and widely-distributed order, 

 of which there are several thousand known species. A well- 

 known British form is the large Garden-Spider {Epeira diadema) 

 (fig. 239), which constructs large regular webs resembling a 

 wheel in shape. The ground-colour varies from yellowish to 

 dark brown, diversified by darker markings, and usually pre- 

 senting a conspicuous white mark on the upper side of the 

 abdomen, whence the German name of "cross-spider" (^Kreuz- 

 spinner), and the French name "cross-carrier" {porte crotx). 

 As in a scorpion, the head and thorax are closely fused together, 

 but the large egg-shaped abdomen is connected by a narrow 

 wasp-waist to the rest of the body, and the segments of which 

 it is made up are so intimately united together that the boundaries 

 between them cannot be made out. 



The first pair of appendages {chelicerd) are two-jointed, and 



