392 REPORT OF STATE GEOLOGIST. 



of the song not lasting more than lialf to three-quarters of a second 

 and is always preceded by the sound which I represent imperfectly 

 by A-r." 



Sub-family DECTICm^. 



All known North American representatives of this sub-family are* 

 apterous or sub-apterous, their tegmina never extending' over more- 

 than two abdominal segments. The antenna? are inserted Ijetween 

 the eyes, nearer the summit of the occiput than tlie upi)er margin of 

 the labrum. Slit-like foramina (hearing organs) are present near 

 the Ijase of the fore tibia', and these tibia? bear au apical spine on 

 their outer up})er side. The tarsi are all more or less depressed; and 

 iheir first two joints are sulcate lengthwise on the sides; while the 

 first joint of those of the hind legs bears a free plantula beneath its 

 base. 



The sub-family is represented in the Western States by numerous- 

 genera and a large number of species, but east of the Mississippi 

 River but two genera and four species belonging to it have as yet 

 been found. In Indiana but one of these genera, Aflanticus Scudder, 

 represented by two species, is known to occur. However, members- 

 of the otheir eastern genus, Orchesticus Saussure, may in time be 

 found within the State, since one of its species is known from Ten- 

 nessee and another from ^Missouri. From other Deiiicinw the species- 

 of Orchesticus may be distinguished by the armed prosternum, the 

 presence of four terminal spines on the lower side of hind femora, 

 and an ovipositor which curves upward. This last character is the 

 principal one separating them from Atlanficus, whose members have 

 the ovipositor straight. 



XLVIIl. Atlaxthts Scudder (18!)4). 



The meud)ers of this genus are Loeustida^ of large size, in whieli 

 the pronotum extends }n\v\< over the first joint of the abdomen, thus 

 forming a l)uckler or shield for the back. Face broad, rounded, but 

 slightly oblique. Eyes snuill, sub-globose. \Vrtex with a l)lunt de- 

 curved projection between the antenna'. Pronotum truncate in 

 front, rounded behind, fiatteiunl above, l)ent abruptly downward on 

 the sides. Prosternum armed with two slender, sub-acute spines. 

 Tegmina of the females rudimentary, wholly covered hy the pro- 

 notum; those of the males fairly well developed, extending in our 

 most common species five or more mm. ])ack of the pronotum. The 

 shrilling organ, which is covered by the pronotum, is circular, and 



