ORTHOPTERA. 141 



draws its body and legs from it, and leaves the cast-skin still 

 fastened to the plant. 



3. Acrydium femur-rubrum. Red-legged locust. 



Grizzled with dirty olive and brown ; a black spot extending 

 from the eyes along the sides of the thorax ; an oblique yellow 

 line on each side of the body beneath the wings ; a row of dusky 

 brown spots along the middle of the wing-covers ; and the hind- 

 most shanks and feet blood-red, with black spines. The wings 

 are transparent, with a very pale greenish yellow tint next to the 

 body, and are netted with brown lines. The hindmost thighs 

 have two large spots, on the upper side, and the extremity, black ; 

 but are red below, and yellow on the inside. The appendages at 

 the tip of the body in the male are of a long triangular form. 

 Length from | inch to 1 inch ; exp. 1^ to If inch. 



The red-legged locust was first described by De Geer from 

 specimens sent to him from Pennsylvania, and I have retained the 

 scientific name which he gave to it. It is the Gryllus (Locusta) 

 erythropus of Gmelin, and the t^crydium femorale of Olivier. 

 It appears to be very generally diffused throughout the United 

 States, and sometimes so greatly abounds, in certain places, as to 

 be productive of great injury to vegetation. I have already de- 

 scribed its prevalence on our salt marshes ; and it seems to con- 

 stitute those large migrating swarms whose flight has been observed 

 and recorded in various parts of this country. It comes to ma- 

 turity with us by the latter part of July, some broods, however, 

 a little earlier, and others later. It is most plentiful and destruc- 

 tive during the months of August and September, and does not 

 disappear till some time in October. 



II. LocusTA. Locusts propcr. 



With the English entomologists, I apply the name Locusta to 

 that genus which includes the celebrated migrating locust, or 

 Gryllus Locusta migratoria of Linnaeus. By the older French 

 entomologists the insects contained in it were united to the genus 

 Acrydium; but Latreille afterwards separated them from Acrydi- 

 um under the generical name of Qldipuda (which means swelled 

 leg), and he is followed in this by Servillc, the latest writer on 



