246 FAMILY VI.— LOCUSTID^. 



continuous z-e-e-e, with an occasional short 2^, caused by the 

 insect getting its wing-covers ready for action after a period 

 of silence. 



A second species (A. dorsalis Burm.) may possibl}^ be 

 found in our state. The two species can be separated by the 

 characters given in the following table : 



a. Front margin of pronotum much shallower, but little 

 more than half as wide as hind margin, the latter 



broadly rounded pacbymerus. 



aa. Front margin of pronotum but little narrowed, almost 



three-fourths the width of the hind margin, the latter 



almost square dorsalis. 



GENUS Anabrus* Haldeman. 



Bulky and large insects. Pronotum extending over the 

 basal portion of the abdomen concealing the rudimentary, 

 s.quamasform elytra; without distinct lateral carinee, and 

 the median carina wanting or visible only on the posterior 

 portion; dorsum of pronotum smooth. Prosternum un- 

 armed. Anterior tibiae with six to eight spines in front, in 

 two rows; tarsi broad, soles concave, the third articulation 

 cordate. Styles of sub-genital plate of males articulated. 

 Ovipositor nearly straight, sword-shaped, two-thirds the 

 length of the body. 



The genus resembles Atlanticus in the shield-like prono- 

 tum and large size of the ovipositor, but differs in having 

 the prosternum unarmed, while in the former genus there 

 are two spines between the base of the front legs. 



Anabrus purpurascens Uhler. 



This dark purplish-brown insect, mottled with yellow, 

 occurs in the Red River Valley, where at least one specimen 

 was found near Argyle. Further west, where the insects be- 

 longing to this and other species are very much more com- 



*abros, with the negative prefix an, in allusion to the unprepossessing appear- 

 ance of the insect. 



