304 



ORTHOPTERA 



CHAP. 



developed wings ; sometimes this is the case of the male but, 

 not of the female. Some of the species are highly modified for 

 a desert life, and exhibit a great variation in the colour of the 

 individuals in conformity with the tint of the soil they inhabit. 

 Xipliocera asina (Fig. 184) is thought by Peringuey to be the 

 prey of the extraordinary South African tiger -beetles of the 

 genus Manticora. 



We have already mentioned the tribe Oedipodides ^ as including 

 most of the species of migratory locusts of the Old World. Some 

 striking cases of variation in colour occur amongst the winged 

 Oedipodides. In certain species the hind wings may be either 

 blue or rosaceous in colour ; it is thought that the latter is the 

 tint natural in the species, and that it is due to the mixture of 

 a red pigment with the pale blue colour of the wing ; hence the 

 blue-coloured wings are analogous to cases of albinism. But the 

 most remarkable fact is that this colour difference is correlative 

 with locality. Brunner von Wattenwyl says ^ that the blue 

 variety of Oe. variabilis occurs only in a few localities in Europe 

 he mentions Vienna and Sarepta, and that where it occurs not 

 a single red example can be met with. Similar phenomena occur 

 in other species in both Europe and North America, and L. Bruner 

 has suggested^ that the phenomena in the latter country are 

 correlative with climatic conditions. 



The group Eremobiens, a subdivision of Oedipodides, includes 

 some of the most interesting forms of Acridiidae. Its members 

 have several modes of stridulation. Citculligera flexuosa and 

 other of the winged forms, according to Pantel,^ produce sounds 

 by the friction of the middle tibia against the wing, both of these 

 parts being specially modified for the purpose in the male sex. 

 The most peculiar members of the Eremobiens are some very 

 large Insects, modified to an extraordinary extent for a sedentary 

 life in deserts and arid places. Trimen says ^ that a South 

 African species, Trachypetra hufo, which lives amongst stones, is 

 so coloured that he had much difficulty in detecting it, and that 

 he noticed in certain spots, often only a few square yards in 

 extent, where the stones lying on the ground were darker, lighter. 



^ Monograph, de Saussure, Mem. Soc. Phys. Geneve, xxviii. 1884, No. 9 ; and 

 XXX. 1888, No. 1. 



2 Prod. Eur. Orthopt. 1882, p. 160. ^ Scieiice, xxi. p. 133. 



4 An. Soc. Espan. xv. 1886, p. 273. ^ Nature, iv. 1871, p. 333. 



