400 Dr. Hagen's and the Rev. A. E. Eaton's 
2 — 6 above, have on each side a pale spot behind a darker 
dot, and in the middle of their base a small yellow triangle. 
Up to the middle of the setfe their joints have dark rings 
at the base ; then comes a long black space divided into 
three by fine pale rings ; next come thi-ee joints entirely 
pale ; the rest of the seta is dark. The setfe are plumose 
from the base as far as the terminal dark portion ; their 
long hairs are white on the three pale joints, nearly black 
on the long black space, and dark between it and the base. 
Length of body 8mm., seta 6mm. [The sette of Siphlu- 
rus are rather similar.] 
Subimago. Eyes black, the turban orange, head and 
thorax dull brown, wings ashy-grey. Length of seta 
8mm. 
Page 105. Cloeoii rnfiihim\rax?,s])^trussiihirri\. Now 
some words about your nomenclature. You write E. rus- 
sula, Miiller ; but he wrote rufula. 
[Familiarity Avith the ftmgi of the genus Russula, Fries, 
led me to write s for the old italic f and then to 
double it.] 
Page 108. Centroptihim luteohim. I do not know 
why you have taken ]\1 tiller's E. luteola for this species. 
I do not understand the word " lepidota" used by him ; it 
is not old Latin ; perhaps it means iridescent. Miiller 
Avould not have forgotten to mention the brown tip of the 
abdomen ; or he had seen the female only. Your deter- 
mination is possible ; but that is all that can be said 
about it. 
[The diagnosis of Miiller's species is " E. hiteola, lepi- 
dota lutea Cauda biseta, alis pedibus setisque albis." From 
its position in the book, one would be led to search for the 
insect referred to in Pictet's genus Clo'e. Three species of 
Cloe, Avhose females are yellow, occur in Denmark, \'\t. : — 
Cloeon rufulum, Ccntroptilum luteohim {transhicidum, 
Pict.) and Ba'etis hinocidatus. Of these the first is dip- 
terous, the other two have rudimentary hind wdngs, those 
of the Centroptihim being the smaller. JNliiller describes 
the male of the Cloeon under the name of E. rufula, 
immediately after the diagnosis of E. luteola. He also 
describes the male of the Baetis under the name E. dia- 
])hana, next but one before the diagnosis of E. luteola. 
He notes of E. rufula, " Diaphanam refcrt, at ala3 minores 
nuUas, nee squamulje," which implies that he knew that 
