NO. 1710. NORTH AMERICA'S! DRAGONFTJES^—WILLTAMfiON. 



373 



and the yellow is produced very briefly posteriorly across the trans- 

 verse carina in a small projection on either side of the middorsal line 

 or as a small median squarish continuation; a short subbasal yellow 

 ring on 8, narrowly or broadly interrupted dorsally, not reaching the 

 lower edge of the segment on either side, and bounded posteriorly 

 by the transverse carina (excepting in one male where it is produced 

 dorsally a little beyond the transverse carina); ventrally the pale 

 areas are generally indistinct, most definite on 2, 



Wings hyaline, rarely with the faintest yellowish tinges over limited 

 areas, and with the extreme apices faintly fumose; one specimen has 

 the crossveins very narrowly edged with brown; no trace of costal 

 or subcostal basal brown areas; stigma very dark reddish brown or 

 black. (See fig. 3.) 



Abdominal appendages'^ distinctly different fromillinoiensis,Sibout 

 3.5 mm. long (2.5 in iUinoiensis), the apex more acute, and in profile 

 more upturned, with the lower edge very slightly convex or straight 

 subapically, and parallel with the upper edge, not converging as in 



Fig. 3— Wings of male Mackomia t^niolata, Bluffton, Indiana, August 6, 1905. 



iUinoiensis; basal lateral external carina always present, but the 

 tooth at its apical termination is always small and may be entirely 

 wanting; a more or less distinct basal external pale area; inferior 

 appendage of usual form, very slightly shorter than the superiors. 



Female. — Similar to the male, but lateral spots on frons generally 

 present, though less distinct than dorsal spots. 



Abdominal spots similar, but spot on 7 may be divided or not in 



a Generally in the North American Macromias the appendages lack that strict uni- 

 formity of shape whicli is so marked a specific character in certain groups. Thegreatest 

 variation in the shape of the superior appendages noticed by me is in the form of the 

 apex. It would seem that this is due to the delicate nature of the appendages, espe- 

 cially probably during teneral life, when they may suffer mechanical injuries, or to 

 post-mortem changes, since not infrequently the superior ap])endagesof an individual 

 are not symmetrical. Corduliinse generally have the superior appendages weakly 

 chitinized. 



