SUBFAMILY I.- GRYLLOTALPIN^. 643 



male, 7- or 8-jointed, female; subgenital plate of male large, trans- 

 verse; ovipositor not visible. Both the two known North Ameri- 

 can genera are represented in our territory- The principal litera- 

 ture treating of them is as follows: Saussure, 1S74, 1S77; Scud- 

 der, 1869a ; Blatchley, 1892, 1903 ; R. & H., 1916. 



KEY TO EASTERN GENERA OF GRYLLOTALPINvE. 



a. Front tibiae with four dactyls; hind femora shorter than pronotum. 



I. GRYLLOTALPA. 



aa. Front tibia? with two dactyls; hind femora usually longer than pro- 

 notum. II. SCAPTERISCUS. 



I. GRYLLOTALPA Latreille, 1802, 275- (L., "cricket" + "mole.") 



The principal characters of this genus have been given above 

 under the subfamily heading and generic key. Among all our 

 (Jryllida? these mole crickets rank first in size and singularity of 

 Structure. When full grown they measure from an inch and a 

 fourth to an inch and a half in length, are pale brown in color and 

 have the body covered with very short hairs, giving it a soft, vel- 

 vety appearance. The females have no visible ovipositor, and, 

 externally, may be separated from the males only by the differ- 

 ence in the veining of the uppermost of the tegmina. By their 

 habit of burrowing beneath the soil in search of such food as the 

 tender roots of plants, earthworms and the larva? of various in- 

 sects, the anterior tibia? of these crickets have, in the course of 

 ages, become so modified in structure as to closely resemble the 

 front feet of the common mole, whence the generic name. The 

 dactyls or claws of these tibia? are four in number, the upper two, 

 the larger, being movable; the others immovable. The compound 

 eyes have, on account of the underground life, become much abort- 

 ed, being not more than one-fourth the size of those of the common 

 field crickets of the genus Gryllus. As the mole crickets crawl 

 rather than leap, the hind femora are but little enlarged, and are 

 always shorter than the pronotum. The hind tarsi are short, 

 seldom exceeding half the width of the pronotum. The genus 

 is widely distributed over the earth, three species occurring in 

 the eastern United States. 



KEY TO EASTERN SPECIES OF GRYLLOTALPA. 



o. Hind tibiae not spined above except at apex. 



b. Apex of hind tibiae armed with eight spines, four long ones on in- 

 ner face and four shorter ones on outer; front trochanters short, 

 nearly semicircular, armed with spinous hairs. 



307. HEXADACTYLA. 7 * 



"Kirby considers the characters given under (b) of generic importance and has found- 

 ed (1906, 2) for hexadactyla and allied forms the genus Ncocnrtilla. I prefer to retain 

 all of our species under the old name Gryllotalpa. 



