NORTH AMERICAN HYMENOPTERA. 217 



Head and thorax suboiiacjue, tlie puuctures fine and very close ; furrow which 

 margins the lateral ridges of jiosterior face of middle segment outwardly 

 not foveolate (no yellow on episternum mesopleuralis or middle segment). 



confertus. 



58. — Pygidium broad, flat, not excavated 59. 



Pygidium narrowed apically and excavated 71. 



59. — Recurrent nervure received by the snbraarginal cell in the middle, or about 



the middle 60. 



Eecurrent nervure received by the snbmarginal cell between middle and 

 apes (ocelli forming a low triangle) ; head and thorax with long, dark 



shaggy hair ; entirely deep black liispidiis. 



60. — Ocelli forming a curved line ; mandibles sim])le at apex (SI. 



Ocelli forming an equilateral triangle ; mandibles dentate at apex 64. 



61. — The two convexities of the enclosure of middle segment smooth, polished 



(hind tibiae yellow at base only ; clypeus black) erraii»>. 



The two convexities of the enclosure of middle segment distinctly and ob- 

 liquely striated, subopaque 62. 



62. — Hind tibiae yellow at base only: space between the eyes beneath, at their 

 nearest point of convergence, about equal to a little more than half the 



length of the scape ; form robust ; head large piiigiiis. 



Hind tibiae,, except a dark blotch within, yellow ; space between eyes beneath, 



at their nearest point of convergence, decidedly greater than half the 



length of scape ; form and head as usual in species of this section- • • -63. 



63. — Space between the eyes beneath, at their nearest point of convergence, about 



equal to two-thirds the length of the scape ; clypeus and scape entirely 



yellow flaTiclypetis. 



Space between eyes beneath, at their nearest point of convergence, equal to 

 about five-sixths the length of the scajie ; clypeus black, the scape yellow 



in front only latifrons. 



64. — Antennae entirely and four anterior legs, fulvous ; apical margins of abdom- 

 inal segments broadly testaceous sim i lis. 



Antennae in greater part black, as is likewise the greater part of the four 



anterior legs 65. 



65. — Mandibles yellow in greater jjart 69. 



Mandibles not yellow, black, reddish apically 66. 



66. — Scutellum almost entirely yellow (rarely black), as is likewise the outer side 



of medial tibiae ; yellow on pronotum forming a continuous band. . . -67. 



Scutellum black, or with a minute spot; the medial tibiae yellow on basal 



portion only; yellow on pronotum broken into two, widely-separated 



spots 68. 



67. — Abdomen somewhat longer than head and thorax united, the first segment 

 not broad and narrowed basiilly ; episternal furrow of mesoplenrae form- 

 ing an angle at about its middle. Length 6 mm sciitellatlis. 



Abdomen a little shorter than head and thorax united, the first segment 

 broad ; episternal furrow of mesopleui'ae gently curved. Length 4.5-5 mm. 



lentiis. 



68. — Basal excavated jiortion of middle segment including at least half of the 



enclosed area, with fine longitudinal ridges or striations ; first joint of 



hind and medial tarsi yellow iucaviis. 



TRANS. AM. ENT. SOC. XXII. (28) JUNE, 1895. 



