376 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.37. 



MACROMIA ALLEGHANIENSIS, new species. 



Length of abdomen: Male, 51-54 mm.; average, 52.6; female, 56 

 mm. Length of front wing: Male, 47.5-48 mm. ; average, 47.8 ; female, 

 52 mm. Length of hind wing : Male, 45.5-46 mm. ; average, 45.8; fe- 

 male, 50 mm. Length of first tibia, male, 8. ,3 mm.; hind femur, male, 

 12.1 mm. Length of tibial keel in length of ti})ia, male: First tibia, f ; 

 middle tibia, ^ to I. 



Without trace of antehumeral thoracic stripe. Latero-ventral 

 metathoracic carina very narrowly yellow posteriorly. Yellow ring 

 on abdominal segment 2 interrupted dorsally, not interrupted at 

 the auricles. Costa dark colored. 



Male. — Postclypeus paler than labrum, usually divided by brown 

 into a central and two extremital pale areas; dorsal spots on frons 

 small or wanting. 



Abdominal spots similar to illinoiensis, with the striking difference 

 that the yellow on 7 encircles the segment, so that segments 7-9 have 

 the inferior basal margin of each segment yellow; small spots are 

 present on 5 in 5 of 7 specimens, and are absent on 6 in 6 of 7 speci- 

 mens. 



Wings hyaline, without trace of color; stigma very dark brown or 

 black. 



Abdominal appendages seen in profile similar to illinoiensis, but the 

 superiors are constricted ventrally beyond the base and are slightly 

 widened near the apex; in dorsal view the median lateral external 

 tooth is present, but minute in every case. 



Female. — Dorsal spots on frons larger than in male, about 1 mm. 

 in diameter; postclypeus slightly paler than labrum, both obscured 

 with dark brown and black. 



Abdominal spots present on 3-6, smaller posteriorly and scarcely 

 evident on 6 ; large spot on 7 not encircling the segment as it does in 

 the male; inferior lateral basal spots on 7-9 indistinct or wanting, 

 excepting on 8 in 1 female, where they are conspicuous; dorsally 

 8-10 are uniform black. 



Wings in 1 specimen hyaline; in the other slightly tinged with 

 brown and with veins brown edged, and with a basal trace of brown 

 in the costal space of front wings and in the costal and subcostal 

 spaces of hind wings; stigma black. Two specimens show: Triangle 

 of front wing free, 1; crossed, 3; subtriangle of front wing free, 1; 

 crossed, 3; triangle of hind wing crossed, 4. 



Vulvar lamina similar to that of illinoiensis but apparently smaller, 

 shorter, and with the emargination narrower and deeper. Abdominal 

 appendages similar to those of illinoiensis. 



This species has been confused with illinoiensis. The length of 

 the first tibia in the female is about 9, as compared with 7 in illi- 

 noiensis. The male may be at once recognized bv characters of the 



