466 MR. B. F. CUMMINGS ON 
with this general description; but in the male the angle or 
niche has developed into a deep somewhat rectangular exca- 
vation of the gena, which is carried right back as far as the - 
lower part of the eye and the subocular wart. Above it. is 
bounded by the lower margin of the clypeus. The whole of this 
area (text-fig. 2) is reserved for the cardo and stipes which are 
very closely attached along their inner surfaces. The stipes has 
been forced back close to the head and back upon the cardo, 
both cardo and stipes being almost vertical in direction (text- 
fig. 2, ST & C). The stipes is a long sclerite, narrow at the base, 
broadening out gradually towards the distal end, where the 
palpus is inserted. It apparently gives only the slightest support 
to the maxillary lobe, as the stipes always comes away from 
the latter in dissection with great ease, and the chitinous bar, 
which in other Trichoptera the stipes sends in as a supporting 
connection with it, cannot be discovered. The cardo is much 
reduced, being visible at the side as a narrow chitinous splint. 
Thus the two maxillary palpi completely cover the clypeus and 
front of the head, and their chitinous, convex, outer surfaces 
form a kind of mask or false front, beneath which the chitin of 
the clypeus has become thin and in places delicate and trans- 
parent (text-fig. 4, SC). 
The labrum is fairly large, with a knob or enlarged basal] piece. 
The mandibles, though present, are very much atrophied, but may 
be detected in a careful preparation one on either side of the 
base of the labrum, as a pair of thin pointed splint-like pieces of 
chitin. In most other Trichoptera well-developed mandibles are 
commonly found, 
The basal joint of the antenna requires further description. 
Text-fig. 5 is a sagittal section of the head and gives a view of 
the relations between the maxillary palpus and the antenna. 
Text-fig. 4 gives a view from in front after both the palpi and 
lobes have been removed. 
From an inspection of these figures it should be clear that 
these enlarged basal joints meet each other behind, but are 
excavated in front on their inner surfaces to receive the tips of 
the ascending maxillary palpi. The inner front part of each 
basal antennal joint is scalloped out into a slot into which the 
palpus tip is neatly fitted and locked by means of the little 
upturned process (text-figs. 4&5). The tip of the palpus also 
is modified to serve this end, as is mentioned and illustrated 
further on (see p. 468, Section iv.). 
In addition to the mask or false front to the head formed by 
the palpi there is also a false top to the head formed by these 
two greatly enlarged basal segments of the antenne, which 
extend backwards nearly as far as the occiput, covering nearly 
the whole of the top of the head. The whip-like remainder of 
the antenna springs, as if from the head itself, from the extreme 
anterior corner of this large basal segment. Hach basal segment 
on the inner excavated side is white in colour and composed of 
