162 TERTIARY JXSECTS OF NORTB AMERICA. 



modern t'onns The other, an extinct genus, Bothromicromus, from British 

 Columbia, is very different from any the European Tertiaries possess. 



OSMYU'S Latreille. 



The species we have placed here agrees somewhat closely with the 

 species from amber, Osm. pictus, referred by Hagen to this genus, but differs 

 from it in its lack of any diverse coloring in the wings, as well as in some 

 minor points of the neuration, as in the distance of the outer series of gra- 

 date veinlets from the outer border of the wing, their regular connection 

 with one of the basal branches of the radius, the regularity of the inner 

 series of gradate veinlets, as well as the structure of the cubital region. 

 The two Tertiary species, however, agree together, and disagree with living 

 types in the simple character of the costal nervules, the much smaller num- 

 ber of sectors, and the character of the basal half of the wing, where the 

 sectorial interspaces are regular and broken by few and irregularly scattered 

 cross-veins, instead of being so numerously supplied as to break up the field 

 into an almost uniform and minute reticulation. The two fossil species 

 would therefore appear to form a section apart, (September, 1883.) 



OSMYLUS REQUIETUS. 

 PI. 14, Figs. 3, 8. 



Three specimens, two of them with their counterparts, have been found, 

 in which the wings are particularly well preserved, and in which something 

 also can be made out of the body and the antenna'. The body is of the 

 usual form, the slender antenna; just about the length of the body, composed 

 of multitudinous cylindrical, smooth joints, a little longer than broad and 

 perfectly equal. 



The wings are very large, the extremity of the abdomen reaching only 

 as far as their middle whim closed, and nearly three times as long as broad, 

 broadest a little beyond the middle. They have the shape of those of 

 Clirysopa, the costal margin being suddenly curved downward just before 

 the tip tn inert the upturned curve of the inner margin, which is bent be- 

 yond the middle of the wing and meets the costal margin lx low the middle 

 of the tip of the wing, the latter barely angulated; besides, however, the 

 costal margin is a little expanded near the ba.se ; the costal area, broad at 

 the base ami made a little more so by the slight deflection of the subcostal 



