130 AMERICAN HYMENOPTERA. 



hind the middle (this projection is common to most of the species of 

 the Dunwuckeli group known to me, but it is particularly prominent 

 in niedius, piillatus and this species. It is absent, or practically so, in 

 fnonteztonc^ , carolinus and dahlbomii); extending considerably beyond 

 tips of squamaj. Squamse extending a little beyond heads of sagittte ; 

 their outer lobe almost wanting, being very short and broadly rounded, 

 but the inner lobe well developed and extending mesad considerably 

 beyond the inner margin of the volsella. Shafts of sagittse bent out- 

 ward somewhat in the middle and the outer margins of their heads 

 entire or nearly so, not distinctly serrate. Uncus very broad in the 

 middle, but tapering rapidly to the recurved apex. 



Wi7!gs. — Generally somewhat lighter than those of workers and con- 

 siderably lighter than those of queens, with only slight violaceous 

 reflections. 



Legs. — Mostly dark, though often with a considerable scattering of 

 dirty whitish hairs about their bases. Hind tibiae with outer faces con- 

 vex and hairy throughout, without long fringes or trace of corbiculae. 

 Hind metatarsi with outer faces distinctly concaved, with no long 

 fringes. 



Dimensions. — Length : queen, 20 mm. to 24 ram. ; worker, \\\ mm. 

 to 15j mm. ; male, I3| mm. to 15^ mm. Spread of wings : queen, 47 

 mm. to 51 mm. ; worker, 29 mm. to 33 mm. ; male, 32 mm. to 36 mm. 



The species is here redescribed from five queens, numer- 

 ous workers and four males. 



Habitat. — Mexico; Guatemala (Department of Solola — 

 Olas de Moka — seven workers); Costa Rica (San Jose, three 

 workers); Chiriqui (Boquete, one worker; Bogona, one 

 queen); Ecuador (four queens, one worker and four males). 



This species is possibly most closely related to brevivilhis, 

 which has the same short, coarse pile in the queen caste and 

 which may possibly grade into it. With this possible excep- 

 tion, medius is its closest ally. The females of mexicaniis 

 have a slightly longer malar space than do those of medius. 

 The males of mexicanus apparently never have ferruginous 

 pile on the last dorsal segment of the abdomen, while those 

 of mediiis appear to always have it. See the discussion, fol- 

 lowing the description of medius, for other points of differ- 

 ence between the two species. Also see the discussion, fol- 

 lowing the description of pjiUatus, for points of diiiference 

 between that species and mexicanus. 



The yellow pile, on the specimens of this species before 

 me, varies in shade from pale straw to a good deep yellow. 



