he ret.-iineil the name of Gryllotalpa, under which nil the 

 species had formei-ly been grouped, and to the other applied 

 that of Scaptcriscus y these two groups were sei^arated by 

 the following characteristics. 



In Scop.'crisrns the posterior margin of the sternum of the eighth 

 abdominal pi'[^:;uiont of the $ is produced into a stout prominent cen- 

 tral tooth ; in (injllntdlpa the margin is entire. 



The mesosternal ridge of Gryllotalpa is prominent, and almost 

 equally so tlirougliout; that of Scapteriscus is never prominent on the 

 anterior half of the segment, and is often limited to the posterior 

 half, or is even obsolescent. 



The fore trochanter of Scapteriscus is large; the free portion 

 almost always equals the tibial dactyl in length, and is of about the 

 same size at the tip as at the base; that of Gryllotalpa is proportion- 

 ally small, seldom exceeding half the length of the tibial dactyls; the 

 form is cultrate or lenticular. 



Scapteriscus is furnished with only two fore-tibial dactyls, both of 

 which are movable; Gryllotalpa has two movable dactyls besides a 

 second pair which are immovable. 



Witli but tew exceptions, the hind femora of Scapteriscus more 

 than equal the pronotmn in length, while in Gryllotalpa they are 

 always shorter tlian the pronotum. 



In Gryllolaljia the length of all the hind tarsal joints taken together 

 seldom exceeds half the width of the pronotum, while they equal its 

 whole width in Scapteriscus. 



The hind tarsal claws of Scapteriscus are clothed with short hairs 

 nearly to the tip; those of Gryllotalpa have hairs only at the base. 



Tlie tegmina of Scapterisc «.s', with but few exceptions, cover, when 

 at rest, two-thirds of the abdomen ; in Gryllotalpa they seldom con- 

 ceal more than one-half of the abdomen. 



The nervures of the middle field of the tegnuna in the fenuiles of 

 Gryllotalpa are distant and rather irregular, somewhat resembling 

 those of the males ; in Scapteriscus they are approximate, regular 

 and straight. 



The anal cerci are longer than the pronotum in Gryllotalpa ; shorter 

 in Scapteriscus. 



Finally, the ninth, and sometimes the eighth abdominal segments 

 are furnished above, in Gryllotalpa, with two transverse lateral rows 

 of long hairs directed inwards, as if to keep the long folded wings in 

 place; these are absent from Scapteriscus, where the wings are 

 equally long and similarly folded. 



Only one species of Scapteriscus has been found without the limits 

 of South and Central America, and that — occurring in a single in- 



