ORTHOPTERA. 139 



1. Acrydium. The thorax (prothorax of Kirby) and the wing- 

 covers of ordinary dimensions ; a projecting spine in the middle 

 of the breast ; and a little projecting cushion between the nails of 

 all the feet. 



2. Locusta. The thorax, and usually the wing-covers also, of 

 ordinary dimensions ; no projecting spine in the middle of the 

 breast ; cushions between the nails of the feet. 



3. Tetrix. The thorax (prothorax) greatly prolonged, taper- 

 ing to a point behind, and covering the whole of the back to the 

 extremity of the abdomen ; wing-covers exceedingly minute, con- 

 sisting only of a little scale on each side of the body ; forepart 

 of the breast forming a projection, like a cravat or stock, to re- 

 ceive the lower part of the head ; no spine in the middle of the 

 breast ; no cushions between the nails. 



i. acrydium. Spine-breasted Locusts. 



This word, which is nearly the same as one of the Greek 

 names of a locust, has been variously applied by different ento- 

 mologists. I have followed Latreille and Serville in confining it 

 to those locusts which have a projecting spine or tubercle in the 

 middle of the forepart of the breast between the fore-legs. To 

 this genus belong the following native species. 



1. Jlcrydium alutaceum. Leather-colored locust. 



Dirty brownish yellow ; a paler yellow stripe on the top of the 

 head and thorax ; a slightly elevated longitudinal line on the 

 top of the thorax ; wing-covers semitransparent, with irregular 

 brownish spots ; wings transparent, uncolored, netted with dirty 



Xipkicera. Robust; head not conical, but with a projection between the an- 

 tennae ; face vertical ; antennae rather short, flattened more or less, and tapering 

 at the end ; a spine between the fore-legs on the breast; wing-covers about as long 

 as the abdomen, obtuse or notched at the end ; thorax with three elevated crested 

 lines, which are frequently notched. 



Romalea. Very thick and short ; head obtuse ; face vertical ; antennae short, 

 of equal thickness to the end, seventeen or eighteen jointed ; thorax with a some- 

 what elevated crest ; a spine between the fore-legs on the breast ; wing-covers and 

 wings much shorter than the abdomen. 



The first two of these genera seem to connect the cone-headed grasshoppers 

 with the locust family, while the last two approach nearer to the genus Acrydium; 

 many foreign genera, however, are interposed between them. 



