1913.1 NATURAL SCIENCES OF PHILADELPHIA. 



241 



According to Karsch's clescription,^^' Nenragrion agrees with 

 Phenacolestcs in characters above numbered 2 (but for the hind wings 

 only), 3^ 8, 10, 12, 14 (in so far as "Der Mediansector entspringt aus 

 dem Principalis vor der vom Nodus absteigenden Ader"), and 16a, 

 and differs from Phenacokstes in the following characters: 



2. Only two antenodals on the front wings. 



3. Postnodals 20-21. 



11. Rs separates from M1+2 near the first postnodal cross-vein. 

 13. Arculus distal to the normal second antenodal. 

 156. Between Ma and M4 probably only one row of cells to margin. 

 176. Between M4 and Cui probably only one row of cells to margin. 



18. Cubito-anal cross-vein apparently proximal to ("vor," not 



"von"?) the level of the first antenodal. 



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



cells. 

 21. Anal vein separates from the hind wing-margm (a) at the level 

 of the arculus and therefore (6) distad to the level of the 

 cubito-anal cross-vein. 



Comparison of Rhipidolestes (aculeata) with Phenacolestes. 



{Rhipidolestes aculeata inhabits Formosa.) 



According to the description and figure of Dr. Ris (1912), these 

 iwo forms agree in the characters above numbered 1, 5, 6, 7, 8, 9, 

 10,=*^ 12,35 i5ff^ iQa (and perhaps 166), 18, 19, and differ in the fol- 

 lowing characters possessed by Rhipidolestes: 



2. Only two antenodals. 



3. Postnodals about 22 (front wing) and 21 (hind wing). 



4. Stigma, although having its proximal edge of about the same 



obliquity as in Phenacolestes, is shorter proximo-distally and 

 its distal edge is less oblique. 

 11. R.S sei)arates from M1+2 proximad to the subnodus at very nearly 

 three-fourths' distance from arculus to subnodus. 



13. Arculus at the second antenodal. 



14. Ms separates from M1+2 at mid-way from arculus to subnodus. 

 156. Between Ms and M4 at the wing-margin are three rows of cells. 

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



wing-margin three rows of cells. 



20. Area posterior to Cu2 with only one row of cells. 



^* Societas Entomologica VI, p. 10.5, 1891. Neuragrion was described from a 

 single female. 



■■'^"Im Hinterfliugel drei Antecubitalqueradern, deren mittlere aui den bub- 

 costdlramii beschrankt ist." 



35 Each of the three rows in the terminal parts of these M2 and Rs areas may 

 divide itself into two rows at two or three cells' distance from the wing-margin. 



