398 Dr. Hagen's and the Eev. A. E. Eaton's 
phimosa ( $ sub.), Miil., Hag.). On the 26tli and 27th of 
June, 1869, between 6 and 7 p.m., at the border of a large 
pond (Obertisch) near Konigsberg, this species was ex- 
ceedingly abundant. After sunset it disappeared. In a 
short time I was covered with subiniagines preparing for 
metamorphosis. Having sat still a feAv minutes with ex- 
panded "ndngs the subimago exhibited a tremulous motion ; 
the skin split along the whole length of the median dorsal 
suture of the thorax ; the head appeared ; the wings were 
going down in the manner of a roof near the abdomen, and 
by visible peristaltic motion the abdomen and the setc-e 
were got loose, and by continued efforts and ^\Tiggling of 
the body from side to side the thorax and wings slowly (in 
one minute) came out. The legs until then are kept by 
the exuviae quite close to the body, nor can they be ex- 
tended before the wings are entirely fi-ee and suddenly 
erected. As soon as this is effected, the legs take hold of 
something and finish the freeing of the abdomen and setse 
by walking away fi'om the skin. The insect then flies off 
from its seat. The empty skin of the subimago is very 
dehcate in texture, snow white, and the thorax is gray 
with a grayish bundle of crumpled-vip Avings on each side. 
I was unable to find pupa or pupa-skin on the plants in 
the water or on the water. As the subimago Avas of course 
just risen, the insect probably undergoes the transforma- 
tion from nymph to subimago in the water, like Pal. 
longicauda. I pinned several subimagines, and found 
that the thorax afterwards underwent the metamorphosis, 
and so the specimens are half imago half subimago. 
Perhaps this fact may explain some descriptions in the 
authors which are not applicable to known living species. 
All specimens in a collection Avith the A\Tings bent doAATi 
may be suspected of being in this transition state ; but the 
imago sometimes assumes the same posture Avhen pinned. 
Concerning the ocelli, Pictet has a very important eiTor. 
The tAvo lateral ocelli, shortly stalked, are very near the 
oculi (Adde Burm.), just above the base of the antennae, and 
not, as in Pict. Ephem. pi. xliii. 2, in the middle of the 
fi'ont. The anterior ocellus, situated beloAv the margin, is 
nearly iuAasible from above. It is overlooked in every 
description that the middle seta is longer than the others, 
and that all three of them in subim. $ 2 and imago $ 
very soon after the base are pilose and have a stronger 
pilosity at the tip. I have specimens fi-om Hungary. 
Two males caught after 10 p.m. in another locality are 
