3 °° 
The Ohi'i Naturalist. 
[Vol. Ill, No. 1 
should be hardened in five per cent, formalin. It is an excellent 
type for class work so far as its hard parts are concerned, but its 
muscular system is too highly modified to serve as a tvpe for the 
group. 
It is the only representative of its genus in America, and is 
quite widely distributed. Its larva is characterized by having its 
third pair of legs rudimentary and is supposed to have a very long 
larval stage. 
THE EXTERNAL SKELETAL SYSTEM. 
The body, as in all insects, is divided into a head, thorax, and 
abdomen. The head contains seven segments and bears a curved 
spine on its median dorsal surface, and is articulated posteriorly 
with the prothorax. This segment bears the first pair of legs and 
presents a smooth expanded surface dorsally. It is articulated 
posteriorly with the meso-meta-thorax by a narrow area. This 
constricted area is part of the meso-thorax, which bears ventrally 
the second pair of legs. On its dorsal surface are borne the elytra 
or wing covers. Fused with the meso-thorax is the meta-thorax, 
which bears dorsally the true wings covered by the elytra and ven- 
trally the third pair of legs. The last region of the body is the 
abdomen, composed of eight segments, six of which are visible 
ventrally, but bear no appendages. 
FIXED PARTS OF THE HEAD. 
These are first the epicranium. This term is applied in a 
general way to the dorsal and lateral regions of the head. The 
portion of the epicranium lying posterior to the spine is the vertex 
( i ) and the region lying anterior to and including the spine and 
extending down to a transverse depression near the anterior end 
of the head is the frons (2). On either side of the spine on the 
lateral margins of the head lie the frontal ridges (3) which mark 
the lateral boundaries of the frons. Below the frontal ridges on 
the sides of the head lie the eyes (4). The epicranium extends 
posterior to tjie eye and ventral to it as the gena (5). Running 
back and in from the posterior ventral border of the eye is a slight 
elevation forming the outer wall of a groove into which the an- 
tenna fits when retracted under the head. This is called the an- 
tennal groove (6). The inner border of this antennal groove is 
the genal ridge (7). It is a well marked elevation with its pointed 
anterior extremities free and it forms the outer wall of the deep 
genal emargination (4’) into which the maxilla can be retracted. 
This sclerite (a small chitinized area) surrounding the foramen 
at the posterior surface of the head is called the occiput, but is 
not separated by a definite suture from the remainder of the epi- 
cranium. The clypeus (8) or epistoma lies on the dorsal surface 
