1917.] NATURAL SCIENCES OF PHILADELPHIA. 241 



agreeing fully in general appearance and structure, except in the 

 following characters. The large series before us, though showing 

 frequent slight individual variations, contains no specimen showing 

 a tendency toward arcuata. 



A. cf. Seventh, eighth and ninth dorsal abdominal segments 

 rather sharply produced and distinctly keeled. Pygidium with 

 lateral angles produced in minute, acute, conical projections. Forceps 

 with inner tooth showing an enlarged and knob-like apex.^^ 



9 . Pygidium with lateral angles produced in slender, almost 

 aciculate projections, each nearly one-third as long as the distance 



between their bases Labia nodijer new species 



A A. d^. Eighth and ninth dorsal" abdominal segments weakly 

 produced and keeled. Pygidium with lateral angles produced in 

 moderately stout, acute, conical projections. Forceps with inner 

 tooth tapering to acute apex. 



9 . Pygidium with lateral angles produced in minute, acute points, 

 each scarcely longer than its proximal width Labia arcuata Scudder 



In addition to the diagnostic characters given above, we would 

 add the following to the description of the species. 



Type: cf ; Cacao, Trece Aguas, Alta Vera Paz, Guatemala. April 

 26, 1906. (Barber and Schwarz.) [U. S. National Museum.] 



Size minute, form moderately robust. Entire insect thickly 

 covered with microscopic hairs. Head with vertex moderately 

 convex, showing a very feeble medio-longitudinal suture. Eyes 

 decidedly less than cheeks in length. Antennae with first joint 

 equalling combined length of second and third joints; second quad- 

 rate; third elongate; fourth about three-quarters as long as third; 

 fifth nearly as long as third; succeeding joints elongate ovate, the 

 longest over four times as long as broad. Tegmina and wings 

 normal for group. Scent glands distinct, but not strongly developed. 

 Pygidium perpendicular, broader than long; surface very feebly 

 bilobate, with few subobsolete rugae; lateral margins feebly and 

 evenly convergent distad; caudal margin, between disto-lateral 

 projections, feebly concave. Forceps strongly bowed, enclosing a 

 mitre-shaped area, as broad as long when the arms touch at their 

 apices; excavate in median internal portion, proximad with a decided 

 longitudinal flange and just beyond its extremity is situated ventrad 

 a decided tooth. Ventral surface of abdomen thickly covered with 



1* The proximal ventro-internal flange of the forceps varies in intensity in both 

 nodijer and arcuata, but shows an average more decided development in the latter 

 species. 



