222 
elongata, linearis, apice bicrenata in 
vagina membranacea obtusa latens.” 
The description given by Latreille in his 
Genera Crustaceorum et Insectorum is 
even more complete than his previous 
one. The ligament of the fork is attached 
to the stipes and is its ligament of ar- 
ticulation, allowing the fork to be pushed 
forwards; the fine membrane attached 
to the middle of the fork unites with the 
membrane of the fleshy basal part of 
the maxilla, permitting the fork to siide 
backwards and forwards through the 
fleshy part of the maxilla by means 
of a cone of muscles, just like the 
Ovipositor in microlepidoptera. The 
relaxation of those muscles brings the 
fork and the ovipositor back, without — 
as far as my observations go — any help 
from retractor muscles. The tip of the 
fork slides in a horny ring of the tip of 
the outer lobe, which is easily broken 
by preparation or compression. There- 
fore the arrangement is similar to the 
arrangement in the hemiptera. Never- 
theless, I confess that I know no other 
insect, in which the inner lobe passes 
through the base of the outer one and 
is held in position by an apical annulus. 
The formation of the latter can be thought 
to be produced by lateral teeth growing 
out from the outer lobe and _ finally 
surrounding the inner lobe. But it is 
wonderful that just this most remarkable 
feature, described about a century ago, 
and easily to be ascertained in living 
specimens, has been overlooked by all 
following observers. 
Genus AMPHIGERONTIA. 
Mr. Kolbe has separated four Euro- 
pean species from the genus Psocus 
PSTCORS., 
to form a new genus Amphigerontia. - 
But the genus cannot stand by the 
characters assigned to it. The last two 
species have the rami venae medianae 
interni and submedianae externi connec- 
ted in one point,’ the two other species 
have it not. The North American species 
have those rami either connected in a 
point, or not. There are specimens in 
which the rami are partly united as-in 
Psocus (proper), and other specimens 
in which the ramuli venae medianae in- 
terni are divergent as in Psocus (proper). 
1. Psocus variegatus Latr. 
I have before me 24 specimens of both 
sexes from Europe, all from Germany. 
They live on linden and chestnut; the 
female appears sometimes in swarms. 
All my specimens show longitudinal 
stripes. sometimes black ones, on the 
front, the existence of which is denied 
by M’Lachlan and Kolbe. The yellow 
color of the pterostigma is sometimes 
wanting. One male from Gilgenau, 
Eastern Prussia, has larger orbicular 
eyes than the others, the space between 
the eyes being smaller than the diameter 
of the eyes. All the other males have 
this space larger. The legs are often so 
dark, that they might better be called 
brown. One specimen with rudimentary, 
smoky wings and a rudimentary venation 
is not a nympha (the ocelli present), but 
belongs to the so-called Lachesilla form. 
(M’Lachlan says Lachesis Westw., 
Lachesilla Hagen, but he has overlooked 
that Lachesilla is Westwood’s name; 
ef. Generic Synopsis, Introduction, p. 47, 
158.) I am not able to separate two 
males from Berlin Fills, N. Y., and 
from Dalton, Georgia, from the Euro- 
pean species. The details are given 
