-8- 



2. Shaft of subgenital plate 

 with tooth-like projec- 

 tions 



Shaft of subgenital plate 

 with no ventral tooth-like 

 projections, slender rod 

 arising from lOth segment 

 projects posteriorly 



3. Apex of 10th tergite en- 

 tirely membranous; no 

 sclerotized rod arising 

 from 10th segment 



- Apex of 10th tergite with 

 dark sclerotized area 



fig. 19c 



fig. 20c 



-3 



cristata Morton 1905 



curta K. & R. 1961 

 -4 



4. Subgenital plate truncate, 

 posterior margin truncate; 

 ventral process large 



- Subgenital plate T-shaped, 

 emarginate; ventral pro- 

 cess usually small 



5. Subgenital plate cleft; 

 ventral process very 

 small 



- Subgenital plate not 

 cleft; ventral process 

 variable 



Paleagapetus Ulmer 1912 



1. Lateral process of 9th seg- 

 ment ending in 3 pronged 

 structure 



- Lateral process of 9th seg- 

 ment not 3 pronged 



2. Lateral view: 10th tergite 

 up curved at tip 



- Lateral view: 10th tergite 

 not upcurved at tip 



Rioptila Blickle and Denning 

 1977 



Stactobiella Martynov 1925 



1. Claspers apparently fused, 

 forming a ventral plate 



- Claspers not fused, either 

 elongate or ovate 



fig. 21c 



fig. 22c 



fig. 23c 



dentata K. & R. 1961 



-5 



instabilis Denning 

 1948 



baldufi K. & R. 1961 



-2 



fig. 24a, 24c celsus Ross 1938 



fig. 25a, 25c 



fig. 26a 



fig. 27a, 

 27b, 27 ant. 



guppyi Schmid 1951 

 nearcticus Banks 1936 



arizonica B. &D. 1977 



fig. 28a, 28c 



brustia (Ross) 1938 

 -2 



