240 PROCEEDINGS OF THE ACADEMY OF [May, 



17. Between M4 and Cui are (a) three antenodal cells'^^ and (6) at 



the wing-margin only one row of cells. 



19. Between Cui and Cu2 at the wing-margin only one row of cells. 



20. Area posterior to Cu2 less developed, having only one row of cells. 

 216. Anal vein separating from the hind wing-margin at or distad 



to the cubito-anal cross-vein. 

 22. Anal cross-vein as stated above for Philogenia. 



Comparison of Mesagrion, Heteropodagrion, and Neuragrion 



WITH PhENACOLESTES. 



■ Of three other American genera of the legion Podagrion, Mesagrion 

 Selys, Heteropodagrion Selys and Neuragrion Karsch, each represented 

 b}^ a single species, the first from Bogota, the second from Quito, 

 the third from Ecuador without more definite locality, I have seen 

 no material. 



According to the description of de Selys (1886), Mesagrion agrees 

 with PhenacoJestes in characters above numbered 3, 7 (probably), 8, 

 12, and 16a, and differs from Phenacolestes in the following characters: 



2. Only two antenodal cross-veins. 



10. Between M2 and Rs only one row of cells. 



11. Rs separates from M1+2 distad to the subnodus. 



14. Ms separates from M1+2 a little distad to the subnodus. 

 156 (Probably one row of cells between Ms and M4). 

 17fl. Between M4 and Cm are two antenodal cells and h (probably 

 one row of cells at the wing-margin). 



18. Cubito-anal cross-veins one, situated proximad to the level of 



the first antenodal cross-vein. 



19. (Probably one row of cells between Cui and CU2). 



21. Anal vein separating from the hind margin of the wing (a) distad 



to the level of the arculus, and (b) distad to the level of the 

 cubito-anal cross-vein. 



According to de Selys' description (1886), Heteropodagrion agrees 

 with Phenacolestes in characters above numbered 7 (probably), 10, 



12. 14, and 16a, and differs from Phenacolestes in Nos. 2, 11, 156 

 (probably), 17a (and 6 probably), 18, and 21 in the same particulars as 

 Mesagrion is above stated to differ from Phenacolestes. Heteropodag- 

 rion further differs from Phenacolestes in the following characters : 



3. Postnodals 20-23. 



8. (Probably one^^^ j.^^ Qf ^ells between Mio and M2.) . 



21 Other species of Heteragrion have but two or one antenodal cell (Selys, 1886, 

 pp. 54, 5.5). 



2- Dr. Karsch, in hi.s description of Neuragrion, states that it has "zwei Schalt- 

 sectoren .... zwischen dem Nodal- und Ultranodalsector, " and, further 

 on, that it agrees in this respect with Heteropodagrion, but de Selys' description 

 of the latter is silent on this point, (although not for the same area'of Mesagrion) 

 and, I think, implies the absence of "Schaltsectoren" here. 



