EPHEMERINA. 335 
regard as the epimerum appears to be tlie scleritc e m" (Fig. 2), which 
in the sketch is situated directly under the inetanotuin. 
Sternum. 
Prosternum. This Is a small triangular area situated between the 
insertion of the legs. 
Mesosternum. This is a very large region divided into a proesternito 
and sternite. The former is narrow, as long as broad, the surface con- 
vex. The sternite is divided into two large, long, oval portions extend- 
ing far back of the insertion of the legs. 
Metasternum. This sclerite is very short, small and rudimentary. 
THE ABDOMEN. 
There are ten abdominal segments. The first tergite is wanting, the 
tenth is a supra-anal plate. There are nine urosternites ; the basal is 
large and long, with a pair of spiracles. The lltli uromere may be repre- 
sented by the median articulated appendage situated between the two 
very long multi-articulated cercopoda. The 10th urite is represented 
by two long, oval, parallel plates. 
A remarkable feature of the male Ephemerina is the two pairs of 
jointed appendages rising from beneath the cercopoda. These may 
be regarded as homologues of two pairs of the rhabdites composing the 
ovipositor of the fomale of other insects. The lower pair (Fig. 1 rh) 
is 3-jointed (perhaps 4-jointed), while the upper pair (rh') is 2-jointed. 
Wo know of no other insects which have two pairs of jointed claspers. 
These singular organs may be called rhabdopoda. They appear to be 
homologues of the abdominal feet of Myriapods, the abdominal legs of 
Tenthredinid and Lepidopterous larvae, and the spinnerets of spiders. 
The adult Ephemerina, then, in the lack of mouth-parts, iu the con- 
centrated thorax, and the possession of two pairs of abdominal jointed 
appendages, differ remarkably from the Odonata and other Pliyloptera, 
so that we are nearly justified iu regarding the group as entitled to rank 
as a suborder. 
Order NEUROPTERA (as restricted by Ericlison). 
Suborder 1. Planipennia. 
Family SIALIDiE. 
THE HEAD. 
Corydalus cornutus .' (PI. LII, figs. 1-3.) Head very broad and flat; ver- 
tex remarkably large, broad, long, and flat, forming the bulk of the epi- 
cranium. Ocelli three, large, but the ocellar area is small, with no suture ; 
the ante antennal (orbital) fossae large and conspicuous, transversely 
oval above, beneath curvilinear. No suture between the clypeus and 
