382 LAND ANIMALS 



terranean affinities.* The Orthoptera are important stenothermal 

 warmth-limited insects. If the earth is divided into cool, warm, and 

 hot regions, the relative number of species of the Blattidae plus the 

 Mantidae in each of these regions is respectively 1:4:18, that of the 

 walking sticks (Phasmidae), 1:1.5:35. The butterfly family Synto- 

 midae, also found in the Freiburg area, has a similar distribution pro- 

 portion of 1:3 :63. 18 



The true home of the buprestid beetles is the tropical region, and in 

 our latitudes they appear in numbers only at midday in summer. 

 Among the arachnids, the scorpions are especially stenothermal, 

 warmth-limited animals; the whip scorpions (Pedipalpi) are confined 

 entirely to the tropics. The reptiles form another division of the animal 

 kingdom that is composed of such stenothermal animals. In the direc- 

 tion of the poles, their numbers diminish rapidly. In the entire 



Fig. 110. — Chlamydosaurus kingii, a lizard of Australia, running upright. After 



Saville-Kent. 



Mediterranean region there are 140 species, with 59 species in southern 

 Europe, 21 in central Europe, only 6 in northern Europe; and only 

 2 at Leningrad. Germany with an area of 540,000 sq. km. harbors 12 

 species, Java with 132,000 sq. km. has 122. The w r armer it is, the 

 larger the reptiles become and the more active they are. The wall 

 lizards {Lacerta muralis) of the Mediterranean region reach a much 

 larger size than those in Germany, and the southern green lizards 

 (L. viridis) may be double the length of the northern. 19 The greater 

 activity of the reptiles of warm zones is reflected in the more rapid 

 locomotion of the lizards, which may even run upright on their hind 

 legs, notably the American Crotaphytus and Basiliscus and the Aus- 

 tralian Chlamydosaurus 2 ® (Fig. 110). 



Stenothermal cold-limited animals also occur, but in smaller num- 

 bers. Snails of the genus Vitrina may be seen crawling about among 

 the melting snows; individuals of this genus have been found at an 

 altitude of 3000 m. in the Alps, w r hile in the tropics they are confined 



* The centipede (Scutigera coleoptrata) , the praying mantis (Mantis religiosa), 

 the snail (Ericia elegans), and the green lizards (Lacerta viridis). 



