1913] Biology of May-flies. 413 



Plate L. 

 Fig. 39. Right legs of Ephemerella lata. 

 Pig. 40. Right fore leg of Ephemerella serrata. 

 Fig. 41. Right fore leg of Ephemerella rotunda. 

 Fig. 42. Right leg of Ephemerella deficiens. 

 Fig. 43. Right fore leg of Ephemerella tuberculata. 

 Fig. 44. Right fore leg of Ephemerella cornuta. 



Plate LI. 



(Genitalia of imagos of Siphlurus alternatus.) 

 Rear abdomen of male, F, forceps, ventral view. 

 Right forceps, showing roughened inner surfaces. 

 Rear Abdomen, dorsal view, showing c. s., caudal setae; pp, penes and 



10s. 10th sternite. 

 Rear of abdomen, side view. 

 Dorsal view of penes resting upon the 10th sternite. The white surface, 



c. e., represents the cut surface of the body wall. The large bases of 



the penes, a, lying inside the body have been exposed by cutting away 



the dorsal part of the abdomen. 

 Part of the abdomen of the female, e. v., egg-valve, with the opening 



of the vestibule directly beneath. 

 Inner view of the 7th and 8th sternites with the oviducts, o. v., and the 



seminal receptacle turned backward to show the ventral side of the 



receptacle. 

 Penes removed from the 10th sternite and viewed from the ventral side. 



o. s. d., opening of seminal duct. 

 Egg valve, common vestibule and outline of receptacle and oviducts, from 



without. 

 Rear abdomen of female, dorsal view. 

 Dorsal view of dissection of oviducts and vestibule. The top of the 



vestibule has been cut away and pulled off with the 7th sternite, so as 



to expose the inner surface of the common vestibule, c. v., and seminal 



receptacle, s. r. 

 Rear abdomen, female, ventral view. 

 Rear abdomen of female, side view, e. v., egg valve. 



Plate LI I. 

 Fig. 58. Egg of Leptophlebia. 

 Fig. 59. Egg of Ameletus ludens. 

 Fig. 60. Egg of Tricorythus allectus. 

 Fig. 61. Egg of Chirotonetes albomanicatus. 



Plate LI 1 1. 

 Fig. 62. Egg of Ecdyurus maculipennis. 

 Fig. 63. Egg of Choroterpes basalis. 

 Fig. 64. Egg of Heptagenia pulchella. 

 Fig. 65. Egg of Heptagenia interpunctata. Needham. 



Plate LIV. 

 Fig. 66. Egg of Ephemerella rotunda. 

 Fig. 67. Egg of Ephemerella excrucians. 

 Fig. 68. Egg of Blasturus cupidus. 

 Fig. 69. Egg of Polymitarcys albus. 

 Fig. 70. Egg of Siphlurus alternatus. 



