936 Charles Paul Alexander 



14. Head with a shining triangular spot. [Pachtjrrhina occipitalis Loew. Bed. Ent. Ztschr., 



vol. <S, p. 65. 1.S64.] N. occipitalis (Loew) 



Head unicolorous 15 



15. Wings strongly tinged with brown, especially along the costal region. [Pachyrrhina 



okefenoke Alex. Wash. Univ. Studies, p. 97-98. 1915.] N. okefenoke (Alex.) 



Wings not strongly brown along the costal region 16 



16. Head and thorax yellowish, almost opaque; color in life strongly greenish. [Pachyrrhina 



tenuis Loew. Berl. Ent. Ztschr., vol. 7, p. 297. 1863.] (Plate XLIV, 199.) 



N. tenuis (Loew) 



Head orange except the lateral margins of the vertex; thorax shining. [Pachyrrhina 



sodalis liOew. Berl. Ent. Ztschr., vol. 8, p. 64. 1864.] N. sodalis (Loew) 



17. Segments of flagellum black at the base 18 



Segments of flagellum yellow at the base 20 



18. Wings strongly tinged with yellow; occiput without a clear, shining triangle. 

 [Pachyrrhina xanthosligma Loew. Berl. Ent. Zt.schr., vol. 8, p. 65. 1864.] (Plate 



XLIV, 201.) A^. xanthosligma (Loew) 



Wings not strongly tinged with yellow; occiput with a clear, shining triangle 19 



19. Costal region hyaline; stigma dark brown. [Pachyrrhina abbreviata Loew. Berl. Ent. 



Ztschr., vol. 7, p. 295. 1863.] A'', abbreviata (Loew) 



Costal region darker; stigma yellowish brown. [Pachyrrhina suturalis Loew. Berl. Ent. 

 Ztschr., vol. 7, p. 295. 1863.] N. suluralis (Loew) 



20. Antennae with 13 segments. [Pachyrhina breviorcornis Doane. Ent. News, vol. 19, 



p. 178-179. 1908] N. breviorcornis (Doane) 



Antennae with more than 13 segments 21 



21. Stigma yellowish brown; wing apex not darker; antennae of male 19-segmented. [Pachyrr- 



hina eucera Loew. Berl. Ent. Ztschr., vol. 7, p. 296. 1863.] N. eiicera (Loew) 



Stigma dark brown; wing apex distinctly darkened; antennae of male 16-segmented. 

 [Pachyrrhina polymcra Loew. Berl. Ent. Ztschr., vol. 7, p. 297. 1863.] 



N. polymcra (Loew) 



After the above key was completed, Dietz (1918) published an extensive 

 revision of the American species of the genus. A number of his new 

 species are found within the faunal hmits of this paper. The more sahent 

 characters of the regional species are here briefly summarized, and these 

 species should be considered in addition to the key. 



Nephrotoma perdita (Dietz). (Pages 116-117 of reference cited.) 



Yellow; mouth parts and palpi yellow; occiput with a shiny brown pentagon; thoracic 

 stripes black, narrowly margined with rusty, the lateral stripes curved outward and ending 

 in an opaque black spot; wings grayish subhyaline, stigma brownish black. Wing of female, 

 14.5 mm. (Manitoba, August.) 

 N. hirsutida (Dietz). (Pages 118-119 of reference.) 



Very closely resembling A'^. macrocera, but with the wings sparsely pubescent. Eighth 

 sternite of male deeply emarginate behind and with a digitiform lobe from the base of the 

 notch. Wing of male, 12.5 mm. (Pennsylvania, May.) 

 N. urocera (Dietz). (Pages 119-120 of reference.) 

 N. cornifera (Dietz). (Pages 120-121 of reference.) 



These two species are close to N. okefenoke but are easily separated by the male 

 genitalia. They are from Virginia and North Carolina. 

 N. calinota (Dietz). (Pages 121-122 of reference.) 



Yellow; antennal flagellum bicolorous; frontal prolongation of head dark brown medially; 

 occiput opaque with a brown line; thoracic stripes silvery gray pruinosc, the lateral stripes 



