152 INSECTS INJURIOUS TO VEGETATION. 



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 hindmost 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 f inch to 1 inch ; 

 exp. 1^ to 1| 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) eri/thropvs of Gmelin, and the Acrydium femorale of 

 Olivier. It appears to be very generally diffused throughout 

 the United States, and sometimes so greatly abounds, in cer- 

 tain places, as to be productive of great injury to vegetation. 

 I have already described its prevalence on our salt-marshes; 

 and it seems to constitute those large migrating swarms whose 

 flight has been observed and recorded in various parts of this 

 country. It comes to maturity with us by the latter part of 

 July ; some broods, however, a little earlier, and others later. 

 It is most plentiful and destructive during the months of 

 August and September, and does not disappear till some 

 time in October. 



II. LOCUSTA. Locifsts proper. 



With the English entomologists, I apply the name Locusta 

 to that genus which includes the celebrated migrating locust, 

 or Gryllus Locusta mig-ratoria of Linnseus. By the older 

 French entomologists the insects contained in it were united 

 to the genus Acrydium; but Latreille afterwards separated 

 them from Acrydmm under the generical name of Q^dipoda 

 (which means swelled leg), and he is followed in this by Ser- 

 ville, the latest writer on the Orthoptera. In the insects of 

 this genus the breast is not armed with a blunt spine or tu- 

 bercle, a character which distinguishes the genus Acrydium 

 from it. In other respects these two genera are much alike. 



