1921] NATURAL SCIENCES OF PHILADELPHIA. 205 



cussed at considerable length by Saussure.^^ The following fea- 

 tures have, however, never been given. 



Pronotum very much flattened but with comparatively narrow 

 pale lateral portions showing some slight deflection, greatest width 

 at latero-caudal angles. Tegmina with discoidal sectors almost 

 longitudinal, false longitudinal veins as decided as the veins them- 

 selves and with supplementary false veinlets between these in dis- 

 tal portions. Limbs comparatively short and heavy. Ventro- 

 cephalic margin of cephalic femora armed in distal third with (5 

 and 8) short but decidedly stout spines, terminating in three heavier 

 spines, slightly more elongate in shghtly increasing ratio distad, 

 ventro-caudal margin with (4) heavier, longer spines in distal 

 third. Large pulvilli present between the rather stout, simple, 

 nearly symmetrical tarsal claws. Median segment with a large, 

 transverse, median depression, formed by the fusion of two circular 

 depressions.^^ Supra-anal plate triangularly produced, with a 

 large, straight, heavy spine directed caudad at each side of the 

 broadly rounded apex. Concealed genitalia including at least 

 three very heavy, shghtly curved spines. Subgenital plate as 

 figured. 



Length of body 17-17.6, width of interocular space .9, length of 

 pronotum 4.8-4.8, width of pronotum 6.6-6.5, length of tegmen 

 17.7-18, width of tegmen 5.3-5.7, length of wing 14, width of wing 

 7.7 mm. 



This insect does not belong to the Pseudomopinae, as has been 

 supposed, but is clearly a member of a distinctive group of the 

 Nyctiborinae. This is shown by the general structure, character 

 of tegminal and wdng venation, limb characters and type of male 

 subgenital plate, which type is found in numerous species of this 

 subfamily only. The genus does not agree with the majority of the 

 genera of the Nyctiborinae, showing complete absence of pilosity 

 and only very slightly asymmetrical tarsal claws. 



Nyctibora holosericea Burmeister. 



1838. N[yctihora\ holosericea Burmeister, Handb. Ent., II, Abth. II, Pt. I, 

 p. 502. [Cameta, Brazil. ] 



Gourdonville, French Guiana, 1 cf . 



Charvien, French Guiana, 1 9 . 



The present specimens appear to agree with Burmeister 's two 

 line description of holosericea better than any we have previously 

 seen from South America. Comparing the material here recorded 

 with Central American specimens of N. noctivaga Rehn, the two 

 species, as here recognized, are seen to be very closely related. 



1' Miss. Sci. Mex., Rech. Zool., VI, p. 66, (1870). 



1^ Partially filled with a pale waxy substance, which in drying has become hard, 

 like shellac. 



