PERIXERUS.— DACTYLOTUM. E95 



3. Perixerus variabilis, Rehn. 



Perixerus variabilis, Rehn, Proc. Acad. Nat. Sci. Philad. 1904, p. 541 \ 

 Eab. Mexico, Guadalajara, Jalisco 1 , 



Not contained in the collections studied and unknown to the present writer. 



DACTYLOTUM, Charpentier. 



Dactylotum, Charp. Orthopt. Descript. et Depict, t. 52 (1845) ; Stal, Syst. Acrid, i. p. 33 (1878) ; 

 Scudd. Gen. N. Am. Orthopt. p. 50 (1897). 



The insects which constitute the present genus are all brachypterous, brightly 

 coloured, medium-sized locusts, which are distributed over Northern Mexico and the 

 more arid portions of the Rocky-Mountain regions of North America south of 

 the Yellowstone River. At least six species have thus far been described. They may 

 be separated as follows : — 



Synopsis of the Species of Dactylotum. 



A 1 . The light colour largely orange-yellow or flavous. Tegmina with 

 their dorsal edges nearly or quite touching. 

 b 1 . General colour of the body chiefly pale, the dark markings 

 blackish-brown. Tegmina fully as long as the pronotum. Hind 



femora moderately slender 1 . bicolor, Charp. 



b'\ General colour of the body chiefly black, the pale markings flavous 

 with an orange tinge on the disc of the pronotum. Tegmina 

 much shorter than the pronotum. Hind femora decidedly 



robust 2. flavopictum, sp. u. 



A 2 . The light colour largely orange-vermilion and flavous varied with 

 white. Tegmina usually lateral, seldom, if ever, touching at their 

 dorsal edges. 

 b x . General form rather robust; the sides of the abdomen without the 

 row of pallid spots. Antennae entirely black. 

 c 1 . Tegmina moderately broad, but narrower than in the species 

 falling into the series A 1 , their veins dirty white or straw- 

 yellow. Prosternal spine pale testaceous or dirty white . . 3. variegatum, Scudd. 

 c-. Tegmina (presumably) not especially wide, their veins pale 



green. Prosternal spine heavy, obtuse, ferruginous .... 4. picturatum, nom. n. 

 b'~. General form normal, the sides of the abdomen provided with a row 

 of pale spots. Antennae more or less annulate with testaceous. 

 c x . Tegmina moderately broad, fully as long as the pronotum, their 



veins apple-green. Hind tibiae blackish-blue 5. histricum, Rehn. 



c 2 . Tegmina narrow, decidedly shorter than the pronotum, their 



veins dirty white. Hind tibiae pale glaucous [6. pictum, Thorn.] 



