1870] 219 



GG. Abdomen without central spines upon the edge of the second segment. 



a. Abdomen tessellated in the oi-dinary manner. Posterior tibiae of <J clothed with 



short soft hairs. 



11. Adolescens, Rond. 



aa. Abdomen with a black central dorsal line, and lateral spots upon the posterior 



margins of the segments. Posterior tibiae of ^ bare. 



BB. Wings with spines upon the second longitudinal veins. 



a. Abdomen tessellated in the ordinary manner. 



aa. Abdomen with the spots or patches arranged in lines. 



b. Eyes near together. 



bb. Eyes wide apart. 



12. Affinis, Fall. 

 13. Setipennis, Rond. 



14. DissiMitis, Meig. 

 15. Infantula, Rond. 



AA. Apex of abdomen red in both sexes. 



I. Wings with the second longitudinal veins unarmed. 

 J. Posterior tibiaj of (J bearded upon their inner sides. 



K. Abdomen with two centnd spines upon the edge of the second segment. 



16. HjS.MORRnOIDALIS, Zett. 



KK. Second abdominal segment without central spines. 



a. Black frontal stripe wider than the interval between the stripe and the eye on 



each side. 



17. NuEus, Rond. 



aa. Frontal stripe equal in width to the space between it and the eye. 



18. Ceuentata, Meig. 

 J.J. Posterior tibia; of 6 bare. 



19. H.SMAT0DE8, Meig. 



II. Wings with spines upon the second as well as the fourth longitudinal veins. 



20. HiEMOEEHOA, Mcig. 



1. CAE>*AniA, Lin., Meig., Macq., Zett., Walk., Schiner, Roud. 



striata ? Meig., Macq., TV alt., Zett., Sch. 



ccerulescens ? Zett., Bond. 

 Yellowish or wLitisli-grcy, striped and tessellated with black. 

 Posterior tibife of ^ with long and tliick beard ; middle tibia) also 

 more or less bearded. Four bristles in the dorsal thoracic row bcliiiid 

 the transverse suture, and two central spines on the margin of the 

 second abdominal segment. Length, 4 — 8 lines.* 



Sead : forehead and face prominent, the latter varying in colour from pale golden-3'ellow 

 to pure white, with dark grey reflections when viewed laterally. Frontal space from one- 

 fourth to one-fifth of the width of the head in brradth in <J, and about one-third in 9. 

 Frontal stripe black. Seta; upon the cheeks very small. Arista with longish hairs. 



Thorax and ScutcUiim grey. Three broad black stripes extend the whole length of the 

 back, and are continued more or less distinctly ovr r the scutelluin ; two irregular or broken 

 stripes are also placed on each side. Ten or twelve bristles are arranged upon the sides in 

 two or three irregular rows, and six or seven others in a lino upon each of tlio two lateral 

 broad stripes upon the dorsum, four of which arc always placed behind the transverse suture 

 and two or three before it. Of the posterior ones the two hindmost are the largest, then 

 comes a small one which is sometimes obsolete, and in front of this a stronger one, though 



• Ijy a Ihie, I mean one-twelfth of iiu inch, or slightly more t\i:\i\ two niillitufetres. If, H. M. 



