VOL.68 TERTIARY INSECTS FROM SIBERIA COCKERELL 13 



lower branch), and approximately opposite the fork of fourth vein; 

 the upper branch lying almost parallel to the lower one, not almost 

 erect as in the other division. 



Divided thus, only one Siberian species (P. amagua) falls in 

 division h. The remaining five go in <z, except for the fact that 

 the upper branch (second vein) is not short and suberect as in 

 P. fulvicollis. In the modern Indian fauna, the preponderance is 

 the other way, division h having three species, division a, only two. 

 The common American P. heteroptera Say falls in division a, but 

 has the upper branch (second vein) long and running nearly par- 

 allel with the lower, thus more resembling the majority of Siberian 

 fossils than do the Indian members of this division. P. flagiata 

 Wiedemann, from Guatemala, has the upper branch even more erect 

 than in P. fulvicollis. It would appear that this erect or suberect 

 branch is a character of the tropical species of both hemispheres, 

 or at least, is lacking in those of temperate regions. 



The Siberian fossils may be separated thus : 



Wing less than 6 mm. long 1. 



Wing over 6 mm. long 2. 



1. Cell in fork of vein 3 (2+3) very long and narrow amagua, new species. 



Cell in fork of vein 3 shorter and broader kudiella, new .speces. 



2. Basal corner of second posterior cell at a distance from anterior cross vein 



less (or not more than) the length of cross vein refracta, new species. 



Basal corner of second posterior cell at a distance from anterior cross 

 vein greater than length of cross vein 3. 



3. Third vein before anterior cross vein over 2 mm. long__ redempta, new species. 

 Third vein before anterior cross vein less than 2 mm. long 4. 



4. Upper branch of fourth vein nearly in line with stem- kuznetzovi, new species. 

 Upper branch of fourth vein strongly and abruptly elevated at base. 



obsitula, new species. 



In this key the living P. heteroptera runs straight to P. refracta. 

 In the descriptions, I follow Williston's interpretation of the vena- 

 tion, but as shown below, this may be incorrect in respect to the 

 second vein. 



PLECIA AMAGUA. new species 



Plate 2, fig. 15 



Wing 5.5 mm. long and about 2,3 broad, very pale reddish, with 

 pale veins; fork of third vein extremely narrow, the upper part 

 (second vein) very weak, the lower strong and strongly curved; 

 fork of fourth vein at a distance from anterior cross vein consid- 

 erably greater than length of latter; fork of third vein a little 

 before vertical level of fork of fourth. Anterior cross vein to foi'k 

 of fourth 480 \l. 



Tertiary of Kudia River, Siberia. 



Holotype.—C2it. No. G0606, U.S.N.M. 



