414 PROCEEDINGS OF THE NATIONAL MUSEUM vol. iii 



Pronotum: Length more than half width, 3.28:6.14; transverse im- 

 pression with several widely separated punctures; in a broad irregular 

 band; rest of surface virtually impunctate except for about a dozen 

 punctures laterally on anterior lobe. 



Scutellum: Length and width equal, 3.85:3.85; surface with several 

 distinct, well-separated moderate punctures; apex impunctate. 



Propleuron and mesopleuron: As in generic description. 



Metapleuron: As in generic description, except that a deeply im- 

 pressed, oblique, crenulated line extends laterally from apex of peri- 

 treme (fig. 101). 



Sternites: VI unmodified along posterior margin. 



Terminalia: Ventral genital plates distinctly concave. 



Length of body: 12.75. 



Type data, — Holotype female (USNM 64579), "Bobas, Guatemala, 

 May, 1924, W. M. Mann." 



Discussion. — In punctation the type appears somewhat inter- 

 mediate between holomelas and rugoscutum. This condition led the 

 author to consider the form as opacus Distant until Chnia's notes on 

 the types showed the latter to have the typically bituberculate sixth 

 sternite of holomelas. The taxonomic worth of the impressed crenu- 

 late line extending laterally from the apex of the peritreme (fig. 101) 

 is open to serious question in view of the fact that there was no series 

 to indicate the extent of varia])ility in what might prove to be an acci- 

 dental cuticular fold. 



The specific name alludes to the unmodified sixth sternite of the 

 female. 



Ectinopiis riigosciitiini Signoret 



Plate figures 66, 18.3, 202 



Ectinopus rugoscutum Sigiiorot, 1881b, p. 319, pi. 10, fig. 41. — Lethierry and 

 Severin, 189.3, p. 64. 



Diagnosis. — The numerous punctures on either side of the disc of 

 the head and the coarsely punctured, transversely rugose scutellum 

 will separate this species from the other two in the genus. 



Description.^ — Male : 



Head: Length more than half width, 1.93(1.75-2.08) :2.83(2.73- 

 2.99); interocular width, 1.56(1.49-1.66); anterior outline semicircular; 

 surface of juga with moderate radiating rugae, with numerous (15 or 

 more) fine punctures anterior to ocelli. Antennal segments: I, 0.57 

 (0.53-0.63); II, 0.90(0.83-0.96); III, 0.88(0.80-0.94); IV, 1.32(1.26- 

 1.40); V, 1.48(1.43-1.54). Labial segments: I, 1.24(1.16-1.36); II, 

 2.04(1.66-2.26); III, 1.77 (1.46-1.89); IV, 1.16(1.03-1.20). 



Pronotum: Length slightly more than half of width, 3.20(3.15- 

 3.33): 6.39(6.23-6.75); transverse impression with numerous crowded, 

 coarse, sunken punctures; anterior lobe with a curved band of nu- 



