NEW AMERICAN SCOLYTOID BEETLES — BLACKMAN 385 



thorns Wollaston, and Phfhorophloeus Key. These, as characterized, 

 seem sufficiently different to be considered as distinct genera, and 

 when the genotypes are compared the same is true. However, when 

 the group as a whole is studied, it is found that there are no sharp 

 lines of demarcation between the species groups. Many species can- 

 not be definitely placed in any of the three categories but possess cer- 

 tain characters of one group and certain other characters of other 

 groups. It would seem that the tribe is still undergoing active evolu- 

 tion and that the species groups present such an unusual intergrada- 

 tion of characters that it seems wise to treat them as a single 

 genus under the oldest generic name, Phloeotribus. 



Of the five new South American species described in the fol< 

 lowing pages the first two {Phloeotribus manni and P. argentinae) 

 belong unmistakably to Phloeotribus s. str. Of the other three, P. 

 holiviae and P. harringtoni cannot be placed definitely in either 

 Phloeotribus s. str. or Phthorophloeus Rey, as they have some char- 

 acters of each group. P. jujuya agrees with Phthorophloeus in some 

 respects and with Phloeophthoims Wollaston in others. 



PHLOEOTRIBUS MANNI, new species 



Plate 17, Figuees 26, 27 



Female. — Pronotum piceous-black, opaque; elytra reddish brown, 

 opaque ; 3.11 mm. long, 1.53 times as long as wide. 



Frontal rectangle 1.09 times as long (including epistomal lobe) as 

 wide ; f rons (fig. 27) convex above, impressed between eyes above the 

 usual transverse, arcuate impression between bases of antennae, trans- 

 versely impressed on epistoma ; surface piceous-brown, closely, rather 

 coarsely punctate, with fine, short, appressed hairs ; epistomal margin 

 thickened and liplike, with a large epistomal lobe twice as wide as 

 long, reddish yellow in color with its distal end shallowly emarginate, 

 arising from its posterior distal surface. Eye slightly less than three 

 times as long as wide, wider above middle, with lower half tapering 

 to a very sharp angle. Antennal scape bright reddish brown, slightly 

 longer than club, which is darker and subopaque. 



Pronotum 1.19 times as wide as long, widest at base, posterior out- 

 line extended in median area, posterior angles scarcely rounded, sides 

 and front margin together nearly evenly semicircular; surface 

 opaque, rather coarsely, densely, moderately shallowly punctured, 

 posterior median area scarcely granulate, anterior area scabrous, sides 

 with broad, low asperities larger and higher at anterior angles; vesti- 

 ture of fine, short hairs, with a few larger, stouter hairs intermixed 

 at sides and in front. 



Elytra wider than pronotum and 1.40 times as long, very broad, 

 1.03 times as long as wide ; anterior margins arcuate, strongly crenu- 



