THE SPINE-BREASTED LOCUSTS. 173 



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 

 entomologists. I have followed Latreille and Serville in con- 

 fining it to those locusts which have a projecting spine or 

 tubercle in the middle of the fore part of the breast between 

 the fore legs. To this genus belong the following native 

 species. 



1. Acrydium 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 semi-transparent, with 

 irregular brownish spots ; wings transparent, uncolored, netted 

 with dirty yellow ; abdomen with transverse rows of minute 

 blackish dots ; hindmost thighs whitish within and without, 

 the white portion bounded by a row of minute distant black 

 dots, and crossed, herring-bone fashion, by numerous brown 

 lines ; hindmost shanks reddish, with yellowish-white spines, 

 which are tipped with black. Length, to the end of the ab- 

 domen, If inch ; the wing-covers expand over 3 inches. 



This insect was brought to me, from Martha's Vineyard, 

 by Mr. Robert Treat Paine. It bears a close resemblance in 

 form to Acrydium Americanum of De Geer, 8 a much larger 

 and more showy Southern species. 



2. Acrydium flavo-vittaium? Yellow-striped Locust. 



Dull green or olive-colored, with a yellowish line on each 

 side from the forehead to the tips of the wing-covers ; hind- 



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 Aa-ydium; 

 many foreign genera, however, are interposed between them. 



[ 8 This reference to De Geer is incorrect, no such, species being found in his 

 works; it may refer to Drury. Illustrations I. pi. 49, f. 2. UHLEK.] 



[ 9 This insect was previously described by Say, who calls it A. bivittatus. 

 The difference between the species, as found in New England and that of the 



