ORTHOPTERA. IO 5 



Sub-family III. EREMOBIN^E.* 



This sub-family includes large, plump species, with the general 

 appearance of members of the (Edipodinae. They can be distin- 

 guished from the preceding sub-family by the presence of the ter- 

 minal spine of the outer row of the posterior tibiae (Fig. 940) ; also 

 by the presence of a rough plate on the side of the second abdominal 

 segment (Fig. 95). The vertex is usually broad, flat, or concave, and 



I 



FIG. 94. Legs of Locusts. FIG. 95. First abdominal segment of Ertmobia. 



strongly declivous ; it is then suddenly narrowed and falls off verti- 

 cally to the plain of the antennae. In this place it forms a par! ap- 

 parently of the frontal costa, from which it is separated anatomically 

 by a little transverse ridge. Below this ridge lies the middle ocellus. 

 The eyes are relatively small, and widely separated by the broad 

 vertex. 



This sub-family is represented in our fauna by Ercmcbia mdgna 

 from Arizona. 



Sub-family IV. ACRIDIN^E. 



Of the series of sub-families of Locusts in which the prosternum 

 is armed, representatives of but two have as yet been discovered in 

 our fauna. To the first of these, the Acridinae, belong some of 

 our most common and at the same time some of the most impor- 

 tant species. In this sub-family the head is short, and is rounded 

 at the union of the vertex and front. The front is slightly reced- 

 ing. The antennae are filiform ; and the terminal spine of the outer 

 row of the posterior tibiae is usually wanting. 



This sub-family is represented by many forms in this country. 

 Only those species that are most likely to attract attention are men- 

 tioned below. These can be determined generically by means of 

 the following table : 



* Eremoblnce, ErimObia: eremos (e/a^yuo?), a desert; bioo (ftiooo), to live. 



