SCAPTEKISCTJS. 201 



Hob. Mexico; Guatemala (Champion). — South America, Guiana, Brazil, Peru, 

 Argentina, North Patagonia ; Antilles. 



[3. Scapteriscus variegatus, Burm. 



Gryllotalpa variegata, Burm. Handb. d. Ent. ii. p. 740. 11 (1838). 



Scapteriscus variegatus, Scudd. Mem. Peabody Ac. Sci. i. p. 14 (1869) ; Sauss. Miss. Scient. Mex., 



Orthopt. p. 339. 5 (?). 

 Gryllotalpa parvipennis, Serv. Orthopt. p. 309 (1839). 

 Elytra abbreviata, dimidium abdomen tegentia. Alae elytra paulum superantia. 



Hab. Colombia (Panama V) ; Antilles, St. Lucia.] 



Tribus TRIDACTYLTN^S * 



Tridactylites, Saussure, Miss. Scient. Mex., Orthopt. p. 347 ; Mel. Orth. 5 e fasc. p. 47 f. 

 Tridactylidm, Brunner von Wattenwyl, Prodromus d. Europ. Orthopt. p. 453. 



The two genera forming this group are nearly allied to the true Gryllotalpinae, but 

 differ from them by well-marked characters ; I therefore follow Brunner de Wattenwyl 

 in separating them from the Gryllotalpinae J. The group Tridactylinae has an evident 

 affinity with the Acridiidae. 



Its principal characters are as follows : — 



Short, filiform antenna? ; coriaceous elytra, in repose sometimes united and forming 

 a roof, as in the Acridiidee ; flabelliform wings, divided by a transverse nervure, and 

 when at rest forming at the tip a compressed lamella, as in the Acridiidae ; exceedingly 

 wide hind femora and a very curious elongate armature of the hind tibiae, giving to 

 these insects an enormous saltatorial power § ; two-jointed anterior and intermediate 

 tarsi ; and the hind tarsi with one joint only. 



But the most striking character of this group lies in the fact that the end of the 

 abdomen bears four appendages, which is a unique exception in the Orthoptera. — 

 The homology of these appendages has not hitherto been established with certainty. 

 Dissection shows that the two superior ones (Tab. XI. figg» 3, c — 8, c. — 9, c. — 10, c) 

 are the homologues of the cerci of the Orthoptera, and that the inferior ones (Tab. XI. 

 figg. 3, a. — 8, «. — 9, a) are formed by very curious processes of the inferior valvulae of 



* Explanation of the figures on Tab. XI. figg. 1-7, relating to the genus Tridactylus : — Nos. i, 8, 9, normal 

 numbers indicating the numerical order of the abdominal segments or their homologues ; 9 *, the 9th ventral 

 segment, or infragenital plate ; c, cerci ; a, anal appendages ; vs, the supra-anal plate (or the 10th dorsal 

 segment) ; i, ditto, inferior side. 



t Comp. also : Saussure & Zehntner, " Notice morphologique sur les Gryllotalpiens " [Revue Suisse de Zoologie, 

 ii. p. 403 (1891)]. 



J The Tridactylinae are included under the Gryllotalpinae in my " Synopsis tribuum," anted, p. 198. 



§ Vide Saussure, Miss. Scient. Mex., Orthopt. p. 321. 

 biol. oentr.-amek., Orthopt., December 1896. 2 Dd 



