136 TRUE TALES OF THE INSECTS. 



arid regions on the shores of the Mediterranean Sea. 

 Many are apterous forms, a circumstance that has, 

 according to Saussure, exercised a marked influence on 

 the geographical distribution of the species ; but several 

 species have well-developed wings. Some of the species 

 are modified to a great extent for a desert life, and 

 exhibit a great variety in the tint of the individuals in 

 conformity with that of the soil on which they live. 



Colour Difference Correlative with Locality. 



To the tribe Oedipodides we have already referred as 

 including most of the species of migratory locusts of 

 the Old World. Some remarkable cases of colour- 

 variation have been noted amongst the winged Oedipo- 

 dides. In some species the hind wings may be either 

 blue or red ; it is thought that the latter is the tint 

 natural in the species, and that the blue-coloured wings 

 are a kind of albinism. But the most remarkable thing 

 is that this wing-colour is correlative with locality. In 

 the few localities in Europe where the blue variety of 

 Oe. variabilis occurs, for example, not a single red 

 specimen can be met with. Attention has been drawn 

 to similar phenomena in other species in North America, 

 and L. Brunner suggests that the phenomena in that 

 country are related to climatic conditions. 



