LOCUSTS AND GRASSHOPPERS (ACRIDIID^E\ 133 



But although the linear form and the very long body 

 are common to both, this structure is due to the develop- 

 ment of different parts in the two families. In Phasmidae 

 the prothorax is short, the mesothorax elongate, while 

 in Proscopides the reverse is the case. The great 

 length of head is very curious in these insects ; but the 

 mouth is not thereby brought nearer to the front, but 

 is placed on the lower side of the head, quite close to 

 the thorax. In most cases the sexes differ strongly from 

 one another, and both usually are entirely apterous. But 

 the genus Astroma displays a remarkable exception, 

 and an almost unique condition of the organs of flight, 

 the front wings being absent in each sex, while the 

 female has rudiments of the hind pair which are wanting 

 in the male. 



Of the tribe Tryxalides, Tryxalis pharaonis, Klug, 

 (see Fig. 19) is a handsome species, found in Sicily, 

 Egypt, Algeria, Caucasus, and Andalusia. This insect 

 approaches the Proscopides in form of the head and 

 other characters. The tribe includes a great many 

 species of grasshoppers. It and the Acridiides are the 

 most numerous in species of the family ; and to the 

 latter belong most of the migratory locusts of the New 

 World. 



We come to the tribe Tettigides, a very extensive 

 group of small Acridiidae, remarkable for the shape of 

 the pronotum, which is prolonged backwards as a hood 



