NORTH AMERICAN HYMENOPTERA. 323 



metathorax covered with large fossulets, the upper surface with a large trian- 

 gular enclosure, which contains three ridges, the two outer of which are oblique, 

 the middle ouc straight, the enclosure has also some transverse rugiB ; petiole of 

 abdomen sulcate, but little longer if anything than the first joint of the hind 

 tarsi. Abdomen glabrous; black; mandibles;, except tips, scape in front and tu- 

 bercles white; tegulre, trochanters more or less, apex of four anterior femora, 

 the four anterior and the base of the hind tibife and the tarsi yellowish testaceous. 

 Length 4 mm. 



% ■ — Anterior margin of the clypeus subtruncate or incurved ; inner eye mar- 

 gins rather strongly converging towards the mouth, the space between them at 

 the clypeus is a little greater than that in fraternus. Head shining, indistinctly 

 punctured ; frontal impression strong; head more quadrate than in either ameri- 

 canus or fraternus ; antennse elongate, the apical joints thickened, the last Joint 

 elongate, its tip acute, third joint distinctly longer than the fourth ; scutellum 

 not impressed, if anything the scutellum and postscutellum are slightly elevated 

 into an angle medially; enclosure on upper surface of metathorax forming a 

 large, elongate hexagon, otherwise the metathorax is covered with fossulets; 

 petiole of abdomen decidedly shorter than the first three joints of the hind tarsi 

 united ; black ; clypeus and sides of face silvery ; mandibles, except tips and tu- 

 bercles, white; antennae, except apical joints, which are fuscous, tegulse, four 

 anterior legs entirely, and the posterior legs, except femora and apical two-thirds 

 of tibia?, yellowish testaceous. Length 4 mm. 



Colorado. 



3. Jiiitignius fraternus Say. 



9 • — Clypeus slightly emargiuate medially ; inner eye margins converging but 

 little towards the mouth. Head glabrous, above more quadrate than in amert- 

 canus, scarcely narrowed behind; frontal impressed line strong; antennae elon- 

 gate, scarcely thickened medially, the joints not irregular, the third joint about 

 equal to the fourth in length, possibly the fourth is a little longer, the apical 

 joint somewhat spatulate; dorsulum anteriorly in the region of the impressed 

 lines, very finely and densely punctured, otherwise the dorsulum is glabrous: 

 scutellum distinctly impressed ; metathorax covered with a large fossae, the upper 

 surface with a somewhat fusiform enclosure, which is truncated at the base, the 

 enclosure separated by a medial ridge, and has several transverse rug;e ; trian- 

 gular enclosure on mesopleura proportionately smaller than in americinnis : 

 petiole of abdomen longer than the hind coxte and trochanters combined, about 

 as long as the first hind tarsal joint, strongly sulcate. Abdomen glabrous ; black ; 

 mandibles, except tips, palpi and tubercles, white; antennae, tegulse, tip of ab- 

 domen, the four anterior coxte, the apex of the femora, all the tibia? and tarsi, 

 except the apical two-thirds of the tibiae, yellowish testaceous. Wings hyaline, 

 iridescent, the nervures and stigma testaceous. Length 5. .5 mm. 



"J, .—Anterior margin of clypeus produced in the middle; inner eye margins 

 strongly converging towards the mouth, the space between them at the clyjieus 

 is about one-third less than at the vertex. Head shining, very indistinctly 

 punctured, transverse, but not so much narrowed behind as in americnuus ; 

 frontal impression distinct; antennae elongate, slightly thickened apically. the 

 last joint somewhat spatulate; dorsulum as in the female; scutellum not im- 

 pressed ; enclosure on upper surface of metathorax forming an elongate liexauon ; 



TRANS. AM. ENT. SOC. XIX. DKCEMBER, IStti. 



