THE CANADIAN ENTOMOLOGIST. 99 



I am thus inclined to regard the ovipositor of Grylloblatta as 

 nearly representing that of the common ancestor of the three 

 families of saltatorial Orthoptera, the Tettigonidae having departed 

 least from the original type as regards this structure. Gryllo- 

 blatta has been derived from some primitive type of Blattid or 

 Blattid-like ancestor. 



These relationships are expressed graphically in the accom- 

 panying diagram. 



Locustidae 

 Tettio-oi 



Blattidae >< Grylloblatta 



Primif/'ve Blattid -/t'ke Ancestor 



Explanation op Plate VI. 



Fig. 1. Grylloblatta campodeiformis, 9 type, dorsal view. 

 Fig. 2. Same, lateral view. 



Fig. 3. Same, ventral view of thorax and base of abdomen 

 (front and middle legs of right side removed). 



Fig. 4. Same, mandible. 



Fig. 5. Same, maxilla. 



Fig. 6. Same, labium. 



Fig. 7. Same, labium (above), hypopharynx (below). 



Sp.i, Sp.2, Sp.3, Sp.9, Spiracles; Mseps mesepisternum; 

 Msepm, mesepimeron; mteps, metepisternum, mtepm, metepi- 

 meron, C. S., cervical sclerites; Sti, St2, Sts, pro-, meso- and meta- 

 sterna. 



