169 



EXPLANATION OF THE PLATES. 

 Plate I. 



The drawings were made with a camera lucida, using a Bausch and Lomb }(-, objective 

 with the lower lens removed and a 2-inch eyepiece. 



Fi^. 1. Jiyi'i aoindh (Say). Blufftou, Lid., August 18, 1900, E. B. Wil- 

 liamsou. Dorsal view of head, protliorax, and mesothorax of fj', disjointed. 



J— Head. CE, compound eye. 



r> — Protliorax. PL, posterior lobe. AG, anterior groove. 



C — Mesothorax, the metathorax showing underneath. AM, anterior 

 end of mesepisternuni. MIX', middorsal carina. MES, mesepisteniuni. 

 Mf, mesinfraepisternum. IIW, liindwing. F]V, forewing. 



Fig. 2. Argid apicalis (Say). Blutfton, Ind., August IS, 1900, E. B. Wil- 

 liamson. Lateral view of protliorax, and mesothorax. 



.l»S' — Articulating surface for liead. Other lettering as for Fig. 1. 



Plate H. 



The drawings were made with a camera lucida, using a Bausch and Lomb % objective 

 and 2-inch eyepiece. 



1. Argia tibial!.^ (Kamliur). Bluffton, Lid., June 17, 1901, E, B. Will- 

 iamson. Anterior end of mesepisternum of (J". 



2. Argla tlliiallx (Ramlnir). Bluffton, Lid., June 17, 1901, E. B. Will- 

 iamson. Anterior end of mesi'pisternuni of ^ . 



8. Arglo xrdnhi (Hagen). Fort Wayne, Ind., July 18, 1901, E. B. Will- 

 i imson. Anterior end of mesepisternum of (J'. 



4. An/ui sol,il<i (Hagen). Fort Wayne, Ind., July 18, 1901, E. B. Will- 

 iamson. Anterior end of mesepisternum of 9- 



5. ^irgia riohicen (Hagen). Tippecanoe River, Lid., July 2, 1901, E. B. 

 Williamson. Anterior end of mesepisternum of (J". 



6. Argin riolareit (Hagen). Pittsburg, Pa.., June 15, 1899, E. B. Will- 

 iamson. Anterior end of mesepisternum of ^ 



7. Argia apirrdis (Say). Bluffton, Ind., June 2, 1901, E. B.William- 

 son. Anterior end of mesepisternum of cP. 



8. Argia (tpicalis (Say). Blutfton, Ind., June 2, 1901, E. B. William- 

 son. Anterior end of mesepisternum of 9 ■ 



9. Argiii jiutrida (Hagen). Bluffton, Ind., June 17, 1901, E. B. Will- 

 iamson. Anterior end of mesepisternum of (^. 



10. Argia pvtrida (Hagen). Fort Wayne, Ind., July 18, 1901, E. B. 

 Williamson. Anterior end of mesepisternum of 9 • 



