388 ASSIXN1B01XE AND SASKATCHEWAN EXPEDITION. 



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 

 Acrydium 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. 



The following description was taken down in the 

 prairies west of the Souris, where this insect surrounded 

 us in countless millions, and the air from nine until four 

 was filled with them as with flakes of snow. 



Dimensions of the Male Insect. — Length of body, 1 

 inch ; with wings closed 1^ inch ; length of wing cases, 

 thirteen lines ; of wings, 12^ lines. 



Colour. — Of head, bluish-green; of thorax, bluish- 

 green, with two lateral black lines, parallel to the sides of 

 the thorax, and half a fine apart ; intersected at an acute 

 angle by two short black lines, half a line apart. These 

 marks on the female are more distinct. 



Abdomen. — Colour of segments pale bluish-green, with 

 whitish-blue margin ; upper portion of each segment 

 dark brown, especially the superior segments ; wing cases 

 ash-coloured, with brown spots. 



Legs. — Upper surface of posterior legs, brownish- white, 

 with two dark brown spots ; outside of the leg red, in- 

 side, light red. 



Tibia. — Eose-coloured and fringed with two rows of 

 spines. Forelegs yellowish-brown. 



Female, differs from the male in the colour of the 

 cheeks, thorax, and upper portion of the abdomen, these 

 parts being of a brighter green. Legs deeper rose-colour ; 

 under-side of abdomen yellowish-white. Length of the 

 insect, thirteen lines. 



The first authentic account of the appearance of extra- 



