260 THE CANADIAN ENTOMOLOGIST 



Fig. 3. — Genitalia male Siphloniirus alternatus. 

 Fig. 4. — Genitalia male SipJilonisca cerodromia. 

 Fig. 5. — Genitalia male Siphloplecton flexus. 



Fig. 6. — Wings Siphloplecton flexus. 



Fig. 7. — Claws fore leg female SipJilonisca cerodromia. 



Fig. 8. — Ventral colour-pattern on segment of abdomen of 

 S. alternatus. 



Fig. 9. — Ventral colour-pattern on segment of abdomen of 

 S. occidentalis. 



Fig. 10. — Ventral colour-pattern on segment of abdomen of 

 5'. triangularis. 



Plate X — ^Mouth-parts. 



Fig. 1-5. — Labrum, maxilla, hypopharynx, mandible and 

 labrum, respectively, of nymph of SipJilonisca cerodromia. 



Fig 6-10 — Labrum, maxilla, hypopharynx, mandible and 

 labrum, respectively, of Siphloplecton flexus. 



Fig. 11-15. — Labrum, maxilla, hypopharynx, mandible and 

 labrum, respectively, of Siphlonurus triangularis. 



Plate XL— Gills. 



Fig. 1-5. — Gills from Segments 1, 2, 3, 4 and 7, respectively, 

 of right side of nymph of Siphlonurus cerodromia. 



Fig. 6-10. — Gills from Segments 1, 2, 3, 4 and 7, respectively, 

 of right side of nymph of Siphloplecton flexus. 



Fig. 11-15. — Gills from Segments 1, 2, 3, 4 and 7, respectively, 

 of right side of nymph of Siphlonurus triangularis. 



