150 ANIMAL LIFE IN DESERTS 



a Nightjar before it flew, and this in spite of the 

 comparatively large size of the bird. We must 

 admit it as a fact that the prevalent colour of desert 

 animals does render them most difficult to see so 

 long as they remain motionless. 



There is only one important exception to the 

 generaHzation that desert animals resemble in colour 

 the soil on which they live, but it is a most remark- 

 able one ; in many deserts a number of the indigen- 

 ous animals are black. This is not commonly 

 known, but is none the less fact. Speaking generally, 

 it may be said that any desert creature which is 

 not coloured Hke its surroundings is black, for 

 bright greens and blues and reds and yellows are 

 very rare ; and though black animals are not a 

 dominating element in the fauna, they are suffi- 

 ciently numerous to be noticeable in many places 

 in the Great Palaearctic Desert. The most remark- 

 able group of black inhabitants of deserts are the 

 Tenebrionidae, a family of beetles. Members of 

 this family, to which the meal-worm (Tenebrio) and 

 the Cellar Beetle (Blaps) belong, are found in a great 

 variety of environments in nearly aU parts of the 

 world. The majority of them are black, and 

 nocturnal ; the habits and food of these insects are 

 very imperfectly loiown, but it is beHeved that the 

 larvae and adults of most feed on dried vegetable 

 matter, and refuse generally ; possibly their abihty 

 to live on dry food has enabled them to invade the 

 arid areas of the globe. Whatever be the reason, the 

 Tenebrionidae have proved successful in colonizing 

 arid countries, and, as the following Hst shows, aU 



