sTiMT'iTKKS or <;itorsi-; i.ocrsTS. 



the inner wings, sometimes much abbreviated or even want 

 ing: all the tarsi :!-.joinied ; arolia present: size larger, length 

 of female rarely less than 20 mm. Family VI. An: HMD.*:, p. 187. 

 aa. Antennae much longer than the body, bristle-shaped, delicately taper 

 ing; ocelli often wanting; tarsi 3- or 4-jointed: calling organs of 

 male, when present, situated on the anal or dorsal field of the teg- 

 mina: organs of hearing, when present, located near the base of the 

 fore tibis, rarely on the prosternnm; ovipositor (except in certain 

 crickets) an elongated, horny blade or needle, its parts compact. 

 c. Tarsi 4-jointed: ocelli generally wanting; tegmina with sides slop- 

 ing, the calling organ of male, when present, located on their 

 basal half, and limited to the anal area; ovipositor, when ex- 

 exserted, forming a strongly compressed, generally sword-shaped 

 blade, the tip not expanded. Family VII. TETTI<:<>MII>.K, p. 453. 

 cc. Tarsi 3-jointed 25 ; ocelli variable; tegmina flat above, the sides bent 

 abruptly downward, the calling organ of male, when present, ex- 

 tending across both their anal and median areas: ovipositor, when 

 exserted, forming a nearly cylindrical straight or upcurved needle, 

 the tip often enlarged. Family VIII. GRYLLID.K, p. 638. 



Family V. TETRIGID.E. 

 (ACRYDIIDJE.) 



THE GROUSE OR PYGMY LOCUSTS. 



The members of this family 29 are our smallest locusts and 

 among the smallest of Orthoptera. They are easily known from 

 all other Saltatoria by having the pronotum prolonged and taper- 

 ing backward to snch an extent that it reaches to or beyond the 

 tip of abdomen; tegmina rudimentary, represented only by small 

 ova! lobes or scales, placed on the sides of the body and usually 

 covering only a small portion of the base of wings; the latter usu- 

 ally present and well developed, especially in their anal area, 

 though both they and tegmina in a few species wanting; proster- 

 nnm prolonged in front by a half circular u chin piece" which 

 envelopes the maxilla^ ami other month parts like a muffler; 

 arolia absent. The males of most species are much narrower 



2S Rarely in Tridactylina? one- or two-jointed or in part wanting. The antenna? in 

 that subfamily and the Gryllotalpins are shorter than the body. 



2!> The characters separating the grouse locusts from the larger short-horned locusts 

 (Acridida?) are so fixed and striking that I have raised the former to family rank. Not 

 only are the external differential characters between the two families far greater than 

 those separating any two families of Coleoptera, but they present in their spermato- 

 genesis a distinction of family rank. In the subfamilies Tryxalinae and Oedipodinae the 

 spermatogenial number of chromosomes is twenty-three, while in the Tetrigidre, accord- 

 ing to Robertson (Journ. Morph. XXVI, Xo. i) there are fourteen in the female and 

 thirteen in the _ male. Harmon (Biol. Bull. XXIX, No. 4) also found only thirteen in 

 Paratettix. This great reduction in the number of chromosomes is additional evidence 

 in support of their being ranked as a family. I have not followed the rule of basing 

 the family name on the oldest generic one included as it would then be too similar to 

 Acridida>. The student can use Acrydiidne instead of Tetrigidre if he so desire. 



