6 Univcrsiiy of Michigan 



inent 5, 26; segment 6, 24; segment 7, 18; segment 8, 12; 

 segment 9, 8; segment 10, 5 (measured to the apex just at the 

 level of the lower edge of the superior appendage). Height 

 of segment 6 at apex in same ratio, 5 ; of segments 7, 8, 9 and 

 10, each 7. 



The superior appendages are dull colored, similar to 10. 

 They are small, slightly inflated, flap-like organs. Their at- 

 tachment by a narrow base to the membrane which encloses 

 the segment within its denticulated posterior margin, proves 

 conclusively their homology with the superior appendages of 

 the Anisoptera. . Their form is shown in PI. I, figs. 3, 4 and 5. 

 The dorsal surface is convex, the ventral surface is subapically 

 concave, with the larger part of the surface convex, abruptly 

 constricted at the relatively narrow base. The inferior ap- 

 pendage is represented by a low broad tubercle, less developed 

 than the two inferior parts of the anal segment. 



Femora light bluish gray ; first femora black above, the color 

 widest and most dense at apex ; second femora with the dark 

 color paler, the basal two-thirds brown, the apex dark 

 brown; third femora with the apical fourth or fifth 

 dark brown, a narrow stripe of lighter brown the length 

 of the femora on the mid-dorsal surface. First femora 

 with a row of brown bristles on the postero-ventral 

 edge (these "'edges" are only positions, indicated by various 

 rows of bristles, as the femora on all legs are practically 

 round) anterior to which, on the ventral surface, is a longi- 

 tudinal row of very small black spines, anterior to which is a 

 row of larger spines, increasing in size from the base to about 

 the middle of the row, beyond which point they are about uni- 

 form in size, except the most apical one which is about two or 

 three times as long as its neighbors ; basally this row is in the 

 mid-ventral line but it gradually passes forward toward the 



