1913.] NATURAL SCIENCES OF PHILADELPHIA. 237 



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

 slightly distad to the cubito-anal cross-vein. 

 iVote.— The wing figured by Prof. Needham {Genealogic Study, 

 pi. 53, fig. 4) as that of ''Philogenia sp.?" is really that of a Mega- 

 podagrion Selys sens, hit., AUopodagrion Foerster. 



Comparison of Paraphlebia (zoe and abrogata) with 

 Phenacolestes. 



(P. zoe d^ 9 Mexico, P. abrogata cf Guatemala.) 



These two genera agree in the characters above numbered 4, 5, 10 



{abrogata only), 12 {abrogata only), and 156 {abrogata only). 

 These two genera differ in the characters given below; after each 



number the difference shown by Paraphlebia is stated. 



1. Nodus at one-fifth of the wing-length. 



2. Only two antenodals. 



3. Postnodals 40 ±:. 



6. Stronger caudal curvatures of the longitudinal veins generally 



as they approach the hind margin of the wing, although less 

 strongly curved than in Thaumatoneura. 



7. The one row of cells between ]Mi and Mia increases to 3 rows 



{abroqata) or 4-6 rows {zoe) at the wing-margin. 



8. The one row of cells between INIia and M2 increases to 3 rows 



{abrogata) or 4-6 rows {zoe) at the wing-margin. 



9. M2 separates from Mi at one-half {abrogata) or thirteen-thirtieths 



( = .43) of the distance from nodus to stigma {zoe). 



10. Between M2 and Rs at the wing-margin are 3-6 rows of cells 



{zoe) . 



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



12. Between Rs and Ms at the wing-margin are 3-6 rows of cells 



{zoe). 



13. Arculus at or even slightly distal to the second antenodal. 



14. Ms separating from M1+2 at or distad to the subnodus. 



15. Between jNIs and Mi (a) are no cross-veins proximal to the level 



of the subnodus {zoe, abrogata), and (6) at the wing-margin are 

 5-7 rows (front wings, zoe) or 6-11 rows (hind wings, zoe) of 

 cells. 



16. Quadrilateral with (a) its proximal and distal sides subparallel 



or slightly diverging caudad, and (6) its distal side hardly more 

 than one and one-half times as long as the proximal side. 



17. Between :Sl4 and Cui is (a) one, or less than one, antenodal cell, 



and (6) at the wing-margin are 3 (abrogata) or 3-6 {zoe) rows 

 of cells. 



18. Cubito-anal cross-veins two, one between the levels of the first 



and second antenodals, but nearer to that of the first, the other 

 nearly below the middle (or distal to the middle) of the quadri- 

 lateral. 



