124 
ILtinois NATURAL History Survey BULLETIN 
289 290 2si 
SPINOSUS ELACHISTUS : FRIVOLUS 
FRONDALIS CLEPTIS VAGANS 
292 293 294 
PLUTO ANACHRIS INTERCALARIS 
295 296 297 
Fig. 289.—Baetis spinosus, male genitalia. 
Fig. 290.—Baetis elachistus, male genitalia. 
Fig. 291.—Baetis frivolus, male genitalia. 
Fig. 292.—Baetis frondalis, male genitalia. 
Fig. 293.—Baetis cleptis, male genitalia. 
Fig. 294.—Baetis vagans, male genitalia. 
Fig. 295.—Baetis pluto, male genitalia. (After McDunnough.) 
Fig. 296.—Baetis anachris, male genitalia. 
Fig. 297.—Baetis intercalaris, male genitalia. 
Vol. 26, Art. 1 
