146 TERTIAEY INSECTS OF NORTH AMERICA. 



LiBELLULA sp. 



PL 0, Figs, i, 16. 



(LiheUuHna) Sciuld., Bull., U. S. Geol. Geogr. Surv. Terr., IV, 775 (1878). 



Fragments of an abdomen in obverse and reverse are probably to be 

 referred to Libellula only in the broadest possible sense, but they are insuffi- 

 cient to give further determination. They evidently represent four or five 

 of the terminal segments of the body, there being first three segments of 

 equal breadth and a similar lengtli, a little longer than broad, with a sliglit 

 median carina ; and then three others without a median carina and with 

 continually decreasing length, the first of them (probably the eighth seg- 

 ment) half as long as the preceding, but of the same width ; the next half 

 as long as the one which precedes it, but narrower, and the last still narrower 

 (but imperfect). 



Length of the fragment, 20"™; of its third (seventh? abdominal) seg- 

 ment, ^S""; breadth of same, 3 5. 



Green River, Wyoming. One specimen, Nos. 4175 and 4176. 



Suborder PLANIPENNIA Burmeister. 



The collections obtained at Florissant embrace eight genera and thir- 

 teen species of ^^lanipennian Neuroptera. All of the species and four of the 

 genera are new, and belong to four families. The Raphidiidfe are the most 

 numerous, embracing Raphidia, with a single species, and Inocellia with 

 four ; the species referred to Raphidia hardly belongs to it in a strict sense, 

 since the costal vein is excessively short, there are no costal veinlets, and 

 the sectors do not originate obliquely from the radius, but more indirectly 

 by transverse veins ; all the species of Inocellia, which fall into two sections, 

 differ from living types and also from the species found in ( Jligocene amber 

 of the Baltic in having no transverse series of regular discoidal areoles be- 

 low the pterostigma. A single species of Osmylus i-epresents the Heme- 

 robida^, and differs from living forms, as does also the aml)er species, in the 

 .simple character of the costal nervules, the much smaller number of sectors, 

 and the limited supply of cross-veins in the basal half of the wing, giving 

 this region a very different appearance from its rather close reticulation in 

 modem types. It may here be noticed that as a very general rule the neu- 

 ration of the wing is nnicli closer in modern Planipennia than in their Ter- 

 tiary representatives. 



