OETHOPTEEA OF INDIANA. 419 



distinguishing characters of the snb-family arc given in the key. 

 Many of the species are dimorphic as regards the length of the 

 wings, and on this account much confusion in synonymy lias resulted 

 in the past. But three genera of the sub-family occur in the United 

 States, all of which are represented in Indiana. These genera may 

 be distinguished by the following key: 



KFA' TO GENEI5A OF INDIANA (iRYLLIN.E. 



a. Species of small size: last joint of tlie maxillary palpi double the 

 length of the one preceding; hind tibitie furnished with long, mov- 

 able, pilose spines; tirst joint of hind tarsi unarmed above or with 



one row of small teeth LV. Nemobius, p. 419 



aa. Species of medium or large size; last joint of maxillary palpi but 

 little, if any, longer than the one preceding; hind tibiae armed 

 with stout, immovable spines; first joint of hind tarsi sulcate 

 above, with a row of teeth on each side. 

 b. Species of large size; fore tWnce provided with a hearing organ 



on both faces LVI. Gryllus, p. 429 



bb. Species of medium size; fore tibine with hearing organ on outer 

 face only LYII. Miogryllus, p. 442 



LV. Nemobifs Rcrville (18:39). 



Of all the Gryllidffi which occur with us, the little brown ground 

 crickets of the genus Nc?nol)ius are the most numerous and the most 

 social. Unlike their larger cousins, the field cl-ickets, they do not 

 wait for darkness before seeking their food, but wherever the grass 

 has been cropped short, whether on shaded hillside or in the full 

 glare of the noonday sun along the beaten roadway, mature speci- 

 mens may be seen by hundreds during the days of early autumn. 

 Even the tangled masses of sphagnum mosses and other semi-aquatic 

 growth of fen and marsh furnish shelter and food to certain species 

 which, in the ages of the past, have become adapted to a life of such 

 surroundings. 



These ground crickets are all of small size, being never more than 

 half an inch in length. The color is usually a dark brown or pitch 

 black, and the bodies and legs are sparsely clothed with brown hairs. 

 The head and thorax are of nearly equal breadth. The last segment 

 of the maxillary palpus is twice the length of the one precediiig it, 

 and enlarged at the outer end. The anterior tiliia? bear near their 

 base a small oval hearing organ on the outer face. The veins of the 

 wing covers of the female run lengthwise, while in the females of the 

 larger field crickets they run obliquely from both sides. 



