470 PROCEEDINGS OF THE ACADEMY OF [1893. 



produced anteriorly into a strong medial tooth, at the base of the 

 tooth the clypeus is transversely impressed ; front with close, rather 

 coarse punctures, with a distinct, medial, impressed line ; ocelli 

 slightly pitted, forming an equilateral triangle ; top of head and 

 cheeks shining, more finely punctured than the front ; first joint of 

 flagellum a little shorter than the second, which is longer than the 

 third; dorsulum with distinct punctures, those on the anterior portion 

 finest and closest ; scutellum punctured like hind portion of dorsulum; 

 metathorax on sides and posteriorly with coarse striatious, the upper 

 surface with a somewhat triangular enclosure, which is on basal por- 

 tion obliquely ridged, on apical portion transversely ridged ; legs 

 strong, the tibiae and tarsi with a very few weak spines ; wings sub- 

 hyaline, iridescent, the apical margins darker, both recurrent nerv- 

 ures generally received by the second submarginal cell, in one speci- 

 men the first recurrent nervure is confluent with the first transverso- 

 cubital nervure ; abdomen finely, though distinctly punctured, the 

 second and third dorsal segments rather strongly transversely de- 

 pressed basally ; pygidial area triangular, finely and closely punct- 

 ured; black; the abdomen rufous; sides of face, clypeus, sides of tho- 

 rax more or less, and the apical margins of abdominal segments 1-5, 

 silvery. Length 9 mm. 



$ . — Eyes scarcely emarginate within and converging but little 

 towards the vertex ; ocelli situated in a low triangle, the distance 

 between the hind pair more than twice greater than the distance be- 

 tween them and the nearest eye-margin; antenna? shorter than in the 

 9 , joints of the flagellum 1-6 produced into a strong angle or tooth 

 beneath, joints 1-4 much narrowed basally ; from joint six the flag- 

 ellum gradually tapers to the apex ; apical portion of abdomen 

 blackish; last ventral segment roundly emarginate at the apex. 

 Length 7 mm. 



Nevada. 



PISON Spin. 



Pison Spin. Ins. Lig. Spec, nov., t. II, fasc. IV, p. 255, 1808. Kohl, Verb, zool.- 

 bot. Gesell. Wien, XXXIV, p. 180, 1884. 



Head as broad or broader than the thorax. Mandibles without 

 emargination on outer edge ; eyes converging towards the vertex, 

 strongly emarginate within ; ocelli normal, distinct and form a tri- 

 angle ; antenna? tolerably long, placed just behind the clypeus, the 

 flagellum slender, rarely club-shaped ; shoulder tubercles not reach- 



