340 



Deutsch. Ent. Zeitschr. 1912. 



Upper portion of eyes red brown, lower dark. Thorax light 

 brown with a broad yellowish median stripe. Abdomen dorsally 

 reddish with light or translucent spots, 

 and with a short dark streak along the 

 bind border of the first five segments 

 and above the stigmata of the segments 

 1 — 8. Venter pal er , especially towards 

 the apex and with dark brownish ob- 

 long spots or stripes. Forceps and legs 

 pale yellow ; the claws dark. Hind wings 

 colourless. 



Length 7 mm ; wing 7,5 mm. 



The description is made from only 

 one male , preserved in alcohol and col- 

 lected in Misiones. 



Fig. 10. Forceps and 



penis of Callibaetis 



trifasciatus. 



9. Larva of Thraulus. 



One fullgrown larva was found amongst the material , and 



comparing the specimen with the figures on plate 35 in „A revisional 



monograph of recent Ephemeridae" by A. E. Eaton, I have a 



clear conception that it belongs to the genus Thraulus , but on 



Fig. 11. Larva of Thraulus. 

 Head and thorax; a double gill of 2"^ pair. 



the other band I could see that it did not agree in every point 

 with the typical larval form of that genus. I consider Th7\ bellus 

 from Portugal to be the type, which A. E. Eaton also has done. 

 I have already mentioned , that some of the South American 



