Notes on the Ephemeridce. 405 
is quoted. Pictet cites all the authors mentioned ; but 
his citation of Burmeister is doubtful on account of his 
not having seen the types. But I believe Pictet's species 
to be different from that of Fabricius and De Geer. The 
eyes are in Pictet said to be brown ; in De Geer sea-green . 
the abdomen in Pictet " fauve," marked with black ; in De 
Geer very dark brown, nearly blackish : Pictet " Les ailes 
sont transparentes . . . avec des nervures noires, . 
vers I'extremite de la region costale . . . une teinte 
brune ;" De Geer hyaline without colour. Pictet does 
not mention the " abdomen subtus griseum." My type 
from Elberfeld is exactly like your H. venosa, though I 
believe the ventral lobe of the last segment in your figure 
to be not sufficiently rounded ; I did not give the penis 
because it agrees with your vi. 24. The border of the 
ventral membrane is more rounded and has only a tubercle 
at the side ; in my H. venosa from Corsica the border is 
less rounded and has a tooth at the side ; in H. gemmata 
the border is nearly straight, and has a triangular lobe at 
the side. In the last two the two spines between the lobes 
of the penis are wanting ; the form of the penis and the 
ensiform inferior processes are different. The ventral lobe 
of the same segment in the female is also different. I did 
not find these species in your Monograph. I believe that 
E. maculata, Poda, does not belong here. 
[I hardly know whether to attach much importance to 
the preceding discrimina, because they are based upon 
comparisons of dried specimens ; but I give them for 
what they may be worth. The figures of the ventral lobes 
of the females in particular appear to me to be taken fi-om 
distorted examples. Still they might be found of some 
use in investigations of dried specimens. The only very 
positive and trustworthy distinction mentioned is the colour 
of the eyes, — brown in H. venosa, and sea-green in De 
Gear's species.] 
Page 152. H. longicauda. [Add Baetis montana, 
Hag. 1863 (nee Pict.), to the synonymy of this species.] 
Page 153. Heptagenia insignis. [Erase from the 
synonymy " Baetis montana, Hag. 1863 ; (nee Pict.)" 
Dr. Hagen encloses a figure of the forceps and penis of 
his species, "^nd rightly observes that it is distinct fi-om 
H. insignis. His drawing appears to be made after a 
dried specimen ; and I take it to represent the genitalia of 
