374 MEMOIRS OF THE CARNEGIE MUSEUM. 



EXPLANATION OF PLATE XVI. . 



All figures are three-fourths natural size, a, lateral view; h, dorsal view. 



Fig. \. Propter a alata (Say). Gravid female of Ohio-form, half-grown, from the 

 Ohio River, Industry, Beaver Co., Pennsylvania, collected August 30, 1909; C. M. Cat. 

 No. 61.4108. 



Fig. 2. Proptera alata (Say). Gravid female of Lake Erie-form, nearly adult, 

 from Lake Erie, Presque Isle Bay, Erie, Erie Co., Pennsylvania, collected May 21, 

 1909; C. M. Cat. No. 61.4102. 



Fig. 3. Toxolasma parvum (Barnes). Gravid female from Conneaut Outlet, 

 Conneautlake, Crawford Co., Pennsylvania, collected June 17, 1909; C. M. Cat. No. 

 61.4101. 



Fig. 4. Eurynia (Micromya) fabalis (Lea). Male, according to shape, from Alle- 

 gheny River, Walnut Bend, Venango Co., Pennsylvania, collected September 6, 1908; 

 C. M. Cat. No. 61.3376. 



Fig. 5. Eurynia (Micromya) fabalis (Lea). Female, judging from the shape, 

 from the Allegheny River, Walnut Bend, Venango Co., Pennsylvania, collected Sep- 

 tember 6, 1908; C. M. Cat. No. 61.3376. 



Fig. 6. Eurynia (Micromya) iris (Lea). Male from Slipperyrock Creek, Wurtem- 

 berg, Lawrence Co., Pennsylvania, collected June 23, 1910; C. M. Cat. No. 61.4827. 



Fig. 7. Eurynia (Micromya) iris (Lea). Gravid female from Little Beaver Creek, 

 Enon Valley, Lawrence Co., Pennsylvania, collected May 11, 1907; C. M. Cat. No. 

 61.2159. 



Fig. 8. Eurynia (Micromya) iris novi-eboraci (Lea). Male from Conneaut Creek, 

 West Springfield, Erie Co., Pennsylvania, collected May 23, 1909; C. M. Cat. No. 

 61.4091. 



Fig. 9. Eurynia (Micromya) iris novi-eboraci (Lea). Female, judging from the 

 shape, from Lake Erie, Presque Isle Bay, Erie, Erie Co., Pennsylvania, collected July 

 7, 1910; C. M. Cat. No. 61.4831. 



Fig. 10. Eurynia (Eurynia) nasuta (Say). Male from Lake Erie, Presque Isle 

 Bay, Erie, Erie Co., Pennsylvania, collected July 8, 1910; C. M. Cat. No. 61.4840. 



Fig. 11. Eurynia (Eurynia) nasuta (Say). Female from Lake Erie, Presque Isle 

 Bay, Erie, Erie Co., Pennsylvania, collected July 12, 1910; C. M. Cat. No. 61.4840. 



Fig. 12. Eurynia (Eurynia) recta (Lamarck). Male of medium size from French 

 Creek, Meadville, Crawford Co., Pennsylvania, collected September 1, 1908; C. M. 

 Cat. No. 61.3512. 



Fig. 13. Eurynia (Eurynia) recta (Lamarck). Gravid female of medium size 

 from French Creek, Meadville, Crawford Co., Pennsylvania, collected September 1, 

 1908; C. M. Cat. No. 61.3512. 



