204 The Philippine Journal of Science i9i6 



ANISOPTERA 



The Ephemeridse, or mayflies, are represented in the collection 

 by only four or five specimens. Doubtless they are fairly num- 

 erous, as many are recorded from Java and other Malasian 

 regions; therefore I have made a generic table for all genera 

 likely to occur in the Philippines, as far as indicated by their 

 known distribution. 



Key to the genera. 

 a\ Vein 8 plainly forked, and with one (or more) longitudinal vein between 

 the forks; mid and hind legs very short; eyes of male widely 

 separated. 

 b\ First vein ends near middle of costal margin; between vein 9 and 

 its fork only one longitudinal vein; rather few cross veins. 



Palingenia. 

 6'. First vein runs out to near tip; between vein 9 and its fork are 



several longitudinal veins; many cross veins Polymitarcys. 



a'. Vein 8 not plainly forked; if some of its branches appear as forks, then 

 no longitudinal veins between forks. 

 c\ Margin of vdng (of adult) ciliate; only two vnngs; three setae; eyes 

 of male separated; no marginal intercalaries. 



d}. Costal and many discal cross veins Tricorythus. 



d\ No costals and few discal cross veins Caenis. 



c'. Margin of wing (of adult) not ciliate behind. 



e^. Hind wings absent or very slender (more than twice as long as 

 broad, and with but two longitudinal veins; some marginal inter- 

 calaries ; two setae ; eyes of male turbinate, approximate. 



/'. Hind wings present, marginal intercalaries in pairs Baetis. 



/'. Hind wings absent. 



g^. Marginal intercalaries in pairs Pseudocloeon. 



g^. Marginal intercalaries single Cloeon. 



e^ Hind wings present and broad, 

 /i". Vein 9 much curved and ending in hind margin long before anal 

 angle, 

 t^. Three setae, hind wings very small; few marginal intercalaries. 



Thraulus. 

 t'. Two setae. 



j^. A large free space at base above vein 8 Rhoenanthus. 



f. No such free space.... Chirotonetes. 



h'. Vein 9 little curved, nearly parallel to hind margin, and ends 

 near anal angle; several longitudinal veins between 8 and 9. 

 fe\ Cross veins arranged in several series, leaving large free spaces. 



Comproneuria. 

 A;'. Cross veins all over. 



P. Hind tarsi twice as long as the tibiae Atopopus. 



P. Hind tarsi barely longer than hind tibiae Thalerosphyrus. 



Only three specimens have been received ; these belong to the 

 genera Thraulus and Thalerosphyrus; one of them appears to 

 be Thalerosphyrus torridus Walker, described very briefly from 

 the Philippines. 



