150 



Trnrasn Mnseiinis Aarshefter 25. — 1902. 



0).r Tn.7TV 



mittecl light, the 2ncl to 8th dorsal segments (collapsed in 

 the specimen) are narrowly translucent at the joinings and 

 ou each side at their bases, and the setæ become redder 

 (medium Burnt Umber brown) with the joinings ver}^ 

 narrowly opaque. Postero-lateral angles of the 9th abdo- 

 minal segment acute and very small. Forceps dark gree- 

 nish grey, or Bistre 

 gre3^ Front legs Bistre 

 brown or (held to the 

 light) brown Amber: 

 the other legs of a ligh- 

 ter tint (approaching 

 Raw Umber brown). 

 Wings vitreous ; the 

 stronger parts of the 

 longitudinal nervures 

 in the front wings gree- 

 Fig. 6. Ephemerella Aronii. Genitalia ^. j^ish-grev (bistre-grey) ' 



and in the pterostig- 

 matic portion of the marginal area 14 to 16 crossveinlets 

 from Ihe subcosta, nearl}^ all of them forked and their 

 branches anastomosing towards the costa. Dimensions va- 

 riable ; one ^ im. from Finland communicated by Dr. J. 

 E. A r through Dr. Silfvenius of Helsingfors in the 

 year 1905 gives front wing 9 or 10 mm. long; the other 

 from Arctic Norway is larger, — front wing 12 ; exterior 

 caudal setæ about 14 mm. long. 



Hab. Scandinavia : Lærdalsøren, Norway, a single Ç 

 beaten out of Alnus near a bridge about an hour's stroll 

 from the hotel (Eaton, 16. VII, 1902) Avas given to the late 

 Mr. Robert M c. L a c h 1 a n, F. R. S. ; Aleknjarg in Ta- 

 nen, Eastern Finmark, July 1879, one specimen ; a second 

 specimen at Frihedsli in Maalselven (10. VII, 1895), both 

 captured by S. S c h n e i d e r and forwarded me by E s- 



