SMULYAN: NEW ENGLAND TENTHREDELLA. 387 
the edges of woods or along hedges, and they are usually found on 
low-growing plants, or on the lower parts of taller ones. Their 
strongly developed mandibles fit them for a predatory life, and 
the writer has seen evidences of this in connection with his ex- 
amination of cabinet material, having found a number of female 
specimens with the remains of some soft-bodied insect between 
the mandibles. They are even cannibalistic: the larger and 
stronger females when confined in small jars will often turn upon 
the smaller insects, even their own males, confined with them. 
In the writer's experience, this seemed to be more especially true 
of the females of verticalis (Say). 
Mr. E. P. Venables of Vernon, British Columbia, in the Cana- 
dian Entomologist (vol. 46, p. 121, 1914), reports a T. variegata 
(Norton) in confinement feeding greedily upon "house flies." 
External Anatomy. 
Head. 
Plate 4, figs. 1, 3. 
The head when viewed from the front is triangular in outline. 
Viewed from above, it is rectangular in general outline (the 
greater diameter being transverse). It deviates, however, from 
this form quite often by narrowing backward]}^ on each side 
from about the middle of the eyes, assuming the outline of a 
trapezoid in which two of the opposite sides converge more or 
less from front to rear. The latter feature is often quite marked, 
and is fairly constant, within limits, in some species. It is 
more general, or more marked in the male sex (see Sexual Dif- 
ferences). The head is always concave or hollowed out behind. 
The compound eyes are large and prominent and their inner 
margins are strongly convergent ventrally. Their general shape 
is elongate-oval with somewhat sinuous inner margins. 
The areas contiguous to the eyes are spoken of as the orbits. 
Thus inner orbit means the area along the inner margin on the 
front; lower orbit, the area along the lower margin, above the 
clypeus and mandibles, etc. 
The clypeus (nasus, hypostoma, etc., of the older authors) 
is an hexagonal plate bounded above by the central portion of the 
front or frons below the antennae (i. e., the hypcrdypeus) with 
