410 REPORT OF STATE GEOLOGIST. . 



Sul) laiiiily (JUYLLOTALriNMO. 



This sub-family includes Die Ijurrowcrs among our crickets. Tlie 

 spocios have the fore liin])s so modified that the}' can make tlieir way 

 readily l)cneath the surface. The antenna^ arc much shorter and 

 less ta])erin<i' fhan in the species liviiij^' ahove fi'round. '^^Flie oviposi- 

 tor of the female is not visible externally. 



Three genera are represented in Indiana which may Ije separated 

 by the following key: 



KEY TO CENEJ;A OF INDIANA C.RYLT.OTALPIN.T;. 



(I. Spceics of larjre size; fore tihiai broadly expanded, the claws prom- 

 inent; two larffc ocelli present; hind femora slender; tarsi three- 

 jointed LI. Gryllotalpa. p. 410 



(in. S])ecies of small size; fore tibia? not broadly expanded but bearinj; 



three' or four spines at the apex; three small ocelli present; hind 



femora much swollen; tarsi one-jointed or Avantin.c:. 



h. Species more than 5.5 mm. in length; pronotum with a weak 



transverse sulcus; hind tibiic Avith four pairs of long slender 



plates used in swimming'; hind tarsi one-.iointed 



T.II. TniDACTYLXTS. p. 413 



hi). Species less than 5.5 mm. in length; proiu)tnm with no trans- 

 verse sxdcns; hind tibia' Avith a single pair of short plates 



used in swimmiug; hind tarsi Avholly wanting 



LIII. Ellipes, p. 415 



LI. GRYLLOTALrA Linnasus (1767). 



Among all the Gryllidre found in Indiana the mole crickets rank 

 first in size and singularity of structure. A^^^en full grown they 

 measure from an inch and a fourth to an inch and a half in length; 

 are light brown in color and have the body covered with very short 

 hairs, giving it a soft, velvety appearance. The females have no 

 visible ovipositor, and, externally, may be separated from the males 

 only by the difference in the veining of the uppermost of the wing 

 covers, due to the presence of a tympanum in the latter sex. By 

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

 the tender roots of plants, earthworms and the larvae of various 

 insects, the anterior tibiae 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, GnjlJofalpa, 

 from "grylhis," a cricket, and "ialpa.'' a mole. The dactyls or claws 

 of these tibiae arc four in number, the upper two, the larger, being 

 movable; the others immovable. The compound eyes have, on ac- 

 count of the underground life, become much aborted, being not more 

 than one-fourth the size of those of the common field crickets, of 



