426 OETHOPTERA. 



$ . Lamina supra-analis elongata, haud incurva, polita, basi valde foveolata, in medio leviter attenuata, apice 



diiatata, margine postico tridendato, vel angustiore, truncate 

 c? . Lamina supra-analis illi /. incurvi subconformis, paulo latiore, polita, basi subdilatata ac valde foveolata. 



Cerci teretes, apice ineisi vel furcati, ramo supero rotundato, infero producto, conico vel corniforme, vel 



per varietatem minus longo ac obtuso. 

 Var. a. Cerci distincte furcati (fig. 19). — b. Cerci obsolete furcati, ramo supero obliterato, tuberculiformi. 



Figures : — Fig. 16, tbe supra-anal plate of the female. — Fig. 17, ditto, of the male : s, supra-anal plate ; a, anal 

 segment. — Fig. 18, the apex of the supra-anal plate of the male (variety). — Fig. 19, a cercus of the male. 



Hab. Costa Eica {Biolley). 



3. Idiarthron atrispinum, st&l. (Tab. XX. figg. 20, 21.) 



Meroncidius atrispinus, Stai, Recens. Orthopt. 2, p. 84 (1874). 



Idiarthron atrispinum, Brunn. v. W. Monogr. der Pseudophyll. p. 173, t. 7. figg. 7, 7 a, b. 



I. incurvo simillimum ; elytris frequenter unicoloribus ; spinis femorum et coxis subtus nigris ; pectore et ventre 

 frequenter nigris. 



2 . Lamina supra-analis elongato-trigonalis, foveolata, apice truncata. 



c? . Lamina supra-analis quadrata vel sat elongata, recta, rugulosa, basi foveolata, margine postico trilobato, 

 lobo medio trigonali, lobis lateralibus dentiformibus, perpendiculariter deflexis, vel cuneiformibus. Cerci 

 brevissimi, crassi, teretes, intus basi haud dentati, haud attenuati, apice truncati, obtusi, tricipites, 

 frequenter tuberculo interno producto. 



Var. 3 . Lamina supra-analis elongata, apice diiatata, trilobata, fere sicut in I. furcato, at valde brevior et 

 recta, haud incurva. 



Figures: — Fig. 20, the supra-anal plate of the female : s, supra-anal plate; a, anal segment. — Fig. 21, the 

 apex of the abdomen of the male, from above : s, supra-anal plate ; a, anal segment ; c, cerci. 



Hab. Guatemala (Mus. Genavense) ; Costa Rica (Biolley), Cache (Sogers). 



The variety is almost intermediate between /. incurvum and 1. atrispinum in the 

 form of the supra-anal plate, but it has cerci like those of /. atrispinum. 



4. Idiarthron subquadratum, sp. n. (Tab. XX. figg. 22, 23.) 



/. atrispino simillimum ; differ t ab illo : 



3 . Lamina supra-anali concolore, basi lata, processu brevi, quadrato, vel postice leviter angustato, piano vel 



subexcavato, utrinque bicarinulato, margine postico truncato, angulis acutis, vel leviter minute trituber- 



culato. Cerci breves, teretes, apice conici. 

 $ . Lamina supra-anali ejusdem formse quam in maribus, quadrata, subexcavata, marginibus lateralibus deflexis 



margine postico obsolete trituberculato vel subarcuato, in medio angulato vel subdentato. 

 Var. 2 • Statura paulo major. Lamina supra-analis brevis, cornea, nitida, trapezina, apice bidentula, foveolata. 



Figures : — Fig. 22, the supra-anal plate of the female. — Fig. 23, ditto, of the male. 



Hab. Guatemala (Oltramare), Pantaleon (Champion); Costa Eica (Van Patten). 



5. Idiarthron subnotatum, Brunn. 



Idiarthron subnotatum, Brunn. v. W. Monogr. der Pseudophyll. p. 173. 



"Differt ab i". alrispino statura majore, elytris amplioribus, coxis tantum superne minime atro-notatis, 

 ovipositore margine inferiore toto pallido, lamina infra-genitali $ subquadrata." 



Hab. Costa Rica (coll. Bolivar). — Colombia, Bogota. 



