342 Petersen, New and little-known species of Ephemerida fr. Argentine. 



American larvae of Baetis, I have found in „Hamburger 

 Magalhaensische Sammelreise. Ephemeriden. Hamburg 1904" by 

 G. U 1 m e r , where he described and figured a Chilian ^aefe-larva, 

 which differs a good deal from the Argentinian, here mentioned. 

 The shape of head , thorax , abdomen and legs is quite the 

 same as in European larvae. The median seta ciliated on both 



/Jß 



^3ä 



Fig. 13. Larva of Baetis. 



a Labium, h left maxilla, c left mandible (all seen 



from below), d gill. 



sides, and the outer setae on their inner side. Head light brown, 

 Thorax light brown with a fine yellowish median line. Abdomen 

 dorsally brown and with yellow side margins. Setae and legs 

 yellowish. The knee and apical part of the tarsus dark brown. 



Length 8 mm. 



The larvae were found at Bompland , and Mr. P. Jörgensen 

 writes, that they were common in rivulets with rapid current. 



