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PROCEEDINOS OF THE NATIONAL MUSEUM. 



VOL. 37. 



Wings hyaline, venation black, in teneral specimens more or less 

 tinged with yellowash; basal costal and subcostal brown spots often 

 present, in their maximum development reaching the first antenodal; 

 wings sometimes fumose beyond the stigma, especially along the 

 anterior margin; stigma yellowdsh brown to black, apparently 

 depending on age. (See fig. 5.) 



Abdominal appendages seen in profile: The upper edge of superiors 

 nearly flat, a slight postero-dorsal elevation at the extreme apex; 

 lower edge beyond the enlarged base nearly parallel to the upper 

 edge, very slightly converging posteriorly, the apex truncate; seen 

 from above the superiors are lyre-shaped, a short basal lateral 

 external carina terminating in a small tooth near the middle of each 

 appendage; this tooth or projection is variable in size, always small, 

 and sometimes not apparent; on the ventral surface distal to this 



Fig. 5.— Wings of male Macromia illinoiensis, Waterloo, Iowa, June 8, 1906. 



tooth the appendage is denticulated; inferior appendage triangular, 

 curved, and equaling or slightly exceeding the superiors. 



Female. — Postclypeus more obscured than in the male, especially 

 at either extremity; spots on frons larger. 



Abdominal spots larger than in male, excepting on 7 and 8 ; smallest 

 on 5 and 6, where they may be lacking entirely; 7 similar to male; 

 dorsal spots absent on 8, excepting in 2 teneral specimens; inferior 

 lateral basal spots indistinct or absent on 8 and 9. 



Wings hyaline, yellowish brown in several teneral specimens, veins 

 black, brown margined in 2 specimens; basal costal and subcostal 

 brown areas reaching beyond the second antenodal as a maximum; 

 apical fumose area sometimes present, variable in extent, in one case 

 extending basally to nodus; as m the male, the darkest winged speci- 

 mens are teneral; stigma as in male. The wings of 10 females show 

 the following: Triangle of front wing, free 6, crossed 14; subtriangle 

 of front wing, free 4, crossed 16; triangle of hind wing, free 7, crossed 

 13 (compare with same parts in 10 males as tabulated; in rows of 



