106 E. T. CRESSON. 



fourth joint much smaller; posterior tarsi (fig. 3) abruptly curved at base, 

 the first joint broad with a rather deep groove on the outside; apical joint of 

 all the tarsi ferruginous, covered with a silvery white pile ; abdomen convex, 

 shining, delicately punctured, clothed with short pale pubescence at base, 

 longer and more dense on the sides, the apex with long rather dense black 

 pubescence, sixth segment broadly rounded at tip, and obtusely emarginate in 

 the middle; venter concave, polished, a long acute spine on apical middle of 

 first segment, and a short prominent acute carina on apical middle of second 

 segment; one specimen has the pale pubescence extending to the base of the 

 fourth segment, and the last segment has a few long pale hairs mixed with 

 the black. Length .55 — .60 inch. 



Hah. — Colorado, (Ridings, Morrison). Three specimens. A very 

 curiously constructed species, somewhat allied to latitarsis Cress., 

 in the formation of middle tarsi. In the above cut, fig. 1 represents 

 the intermediate tarsi of abnormis, and fig. 2 that of latitarsis; fig. 3, 

 the posterior leg (in part) of abnormis, and fig. 4, that of latitarsis, 

 showing the form of the tibial spurs, which are short and normal 

 in abnormis. 



Osiiiia Integra. — %. — Steel-blue; head and thorax very densely and 

 finely punctured, opaque, thickly clothed with a long erect pale pubescence, 

 tinged with ochraceous above, and most dense on face, where it is silvery- 

 white; anterior margin of clypeus truncate; antennae not as long as head and 

 thorax, black; wings hyaline, faintly dusky on apical margin; legs black, 

 clothed with black pubescence, mixed with pale on anterior pair, tips of tarsi 

 dull testaceous; abdomen shining, convex, very finely punctured, brilliant 

 steel-blue, first and second segments rather thinly clothed with pale pubes- 

 cence, the remainder with shorter black pubescence; sixth segment broadly 

 rounded at tip, a shallow depression on posterior middle, apical margin entire; 

 apiqal segment obtusely emarginate; third ventral segment broadly emar- 

 ginate on anterior middle which is fringed with long golden hair. Length 

 .60 inch, 



Hab. — Colorado, (Morrison). Two specimens. 



Ostnia margiiiipeuuis. — %. — Black, slightly tinged with greenish- 

 blue; head and thorax finely and densely punctured, clothed with a long 

 dense pale ochraceous pubescence, that on thorax above tinged with dull 

 ochraceous, that on clypeus whitish, and that on cheeks mixed with black; 

 anterior margin of clypeus subsinuate; antennae reaching to scutellum; tegulse 

 piceous; wings hyaline, the apical margin conspicuously fuliginous, a fuscous 

 streak in marginal cell; legs black, clothed with black pubescence, that on 

 four anterior femora more or less mixed with pale, that on tarsi beneath red- 

 dish ; abdomen shining, finely punctured, more strongly tinged with blue, the 

 first segment and sides of second and third, clothed with pale pubescence, the 

 remainder with black; sixth segment obtusely notched on apical middle, 

 seventh segment bidentate; apical middle of third ventral segment with a 

 small patch of golden hairs. Length .50 inch. 



Hah. — Colorado, (Morrison). One specimen. This may be the % 

 either of longula or juxta. 



