150 



FAMILY V. TETRIGIDJE. THE GROUSE LOCUSTS. 



bodied than the females and have the subgeuital plate conical or 

 triangular, and supra-anal plate lanceolate or triangular; cerci 

 very .small, cylindrical or conical. The valves of the ovipositor 

 are armed with small rounded teeth on their outer edges, and 

 their extremities are sharply divergent. 



In addition to the characters mentioned the Tetrigid;e have 

 the eyes conspicuous, globular or subelliptic; ocelli three, ar- 

 ranged in the form of a triangle, the median or apical one being 

 in the lower portion of the groove of frontal cost a; antennae 12- 

 to 22-jointed, usually cylindrical or filiform; face with a frontal 

 costa extending down its middle, this often more or less forked, 

 its branches sometimes widely divergent; head above bounded in 

 front by the fastigiuni, the latter usually with a transverse carina; 

 vertex behind the fastigiuni and between the eyes, varying much 

 in form and size and usually divided by a lengthwise median 

 carina ; upper or dorsal surface of pronotum extremely variable in 



t>olttlo on- ANTERIOR CR- 



CL-rTSAL St NUS , / HUMERAL NGLEC?HOULn' 



Fig. 58. Side view of a grouse locust giving the names of the different external 

 parts. The face is shown at the right, the pronotum and head below. (After Han- 

 cock. ) 



form and rugosity, lateral lobes with hind border more or less 

 sinuate, usually with two distinct notches or sinuses, the upper- 

 most one. known as the tegminal or superior sinus, enclosing tli<> 

 base of tegmina, the lowermost or inferior sinus usually much the 

 wider, the median lobe between them variable in form, as is also 

 the lower posterior lobe or angle, beneath the inferior sinus; legs 

 more or less compressed; hind femora much enlarged; hind tibia? 

 with numerous spines ; fore and middle tarsi with only two vis 

 ible segments, the terminal one three or four times as long as the 



