PLATE V 



Fig. 64. Labium Tricorythus, ventral aspect. 



Fig. 65. Hypopharynx, Ameletus. 



Fig. 66. Hypopharynx, Habrophlebia. 



Fig. 67. Hypopharynx, Callibaetis. 



Fig. 68. Right maxilla, nameless Chilean 

 nymph, after Eaton. 



Fig. 69. Left maxilla Rhithrogena, in part. 



Fig. 70. Diatom raker from maxillary palp, 

 Rhithrogena. 



Fig. 71. Labium of Ephemerella, ventral 

 aspect. 



Fig. 72. Maxillary palp, nameless Chilean 

 nymph, after Eaton. 



Fig. 73. Labium Baetis, ventral aspect. 



Fig. 74. Labium Baetisca, ventral aspect. 



Fig. 75. Left maxilla Blasturus, ventral as- 

 pect. 



Fig. 76. 

 Fig. 77. 



Fig. 78. 



Labium Oligoneuria, ventral aspect. 

 Left maxilla Hexagenia, ventral 

 aspect. 



Left maxilla Baetisca, ventral as- 

 pect. 



Diatom raker, maxilla Rhithrogena. 

 Labium, nameless Chilean nymph, 

 al~!er Eaton. 



1 eft maxilla Caenis in part, ventral 

 aspect. 



Left maxilla Ephemerella dcHeiens, 

 ventral aspect. 



Right maxilla Lachlania, ventral 

 aspect. 



Labium Epeorus, ventral aspect. 

 Left maxilla Hagenulus, ventral 

 aspect. 



36 



