390 Dr. Hagen's and the Rev. A. E. Eaton's 
Page 47, line 2. [For russulum read rufulum.] 
Page 47. [Merge with Baetis undatus, B. fluctuans, 
pictus and ferrugineus.] 
Page 47. [Baetis ? [albus] and ? [Ephoron leukon] are 
probably Polymitarcys puella.] 
Page 48. [" Ileptagenia ? [tessellata, Hag.'] Paget 
Sound ; Washington," is almost certain to be Leptophlebia 
colombiie, p. 46.] 
Page 54. Lachlania. — I examined 19 $. They are 
not in very good condition ; the eggs in most are either 
deposited or just coming out. The ventral segment with 
the eggs coming out seems open at the sides. This I have 
designated (perhaps improperly) the egg-valve. The speci- 
mens are not in sufficiently good condition to enable one 
to be entirely sure about this formation. 
[1 have examined a $ Lachlania in INIr. M'Lachlan's 
collection, and find no trace of an extension of membrane 
in the form of an egg- valve, such as may be found in Hej)ta- 
yenia. The oviducts are unprotected as in E'pheinera.~\ 
Pages 55, 5Q. I have compared the figures of Olif/. 
pallida with my type, and believe them to be correct for 
the forceps. The forceps is 3-jointcd, one long basal and 
two short apical joints. The membrane below is rounded 
before, and the penis is nearly covered by it. O. Rhenana 
has the forceps three-jointed, the penis bifid and con- 
siderably longer than the quadrangular membrane below. 
In both species the forceps is more membraneous than 
corneous. I remark purposely that of both species I have 
only one male imago before me, and only one female imago 
of O. pallida. In Imhoff's collection in the Museum, I 
found seven $ and more $ subimagines of O. Rhenana, 
all alike as to the penis and the membrane below it, 
excepting one, which is more similar to O. pallida. ' I am 
not sure that these males are not imagines, the imago 
described from Von Heyden's collection being not at hand 
now. Two female imagines from Elberfeld are very 
similar to the female O. pallida. Of course new observa- 
tions are necessary. 
[In August, 1871, I again took Oligoneuria Rhenana 
i imago on board a steamer at Cologne. The structure 
