498 Mr. Newport on the Anatomy and 
the branchiz have the same simple form, but instead of being distributed 
over the whole surface of the body they are collected into tufts, one on each 
side of each abdominal segment. In the Hydropsyches also they are setaceous 
and tufted, not merely at the sides of the abdomen, but also at the termina- - 
tions of the caudal styles. In the Sialide, which come near to the Perlide, 
the respiration of the larva is both caudal and abdominal. Each segment of 
the abdomen in Sialis has a pair of single, articulated, lateral branchiz pro- 
jecting from it, while the caudal styles also are respiratory organs, as in 
Agrion and Hydropsyche. | 
In some of the Perlida, as in Nemoura, Pictet has shown * that the branchice 
are not tufted, as in Perla, although they are almost entirely confined, as in 
that genus, to the thoracic instead of the abdominal segments. They consist 
of single cylindrical appendages, as in Sialis, and project from the pectoral 
surface of each of the thoracic segments, three pairs from each. In the true 
Perlide t the branchiz are tufted, are almost entirely thoracic, and are found 
in the whole of the species, except only in two or three, Perla virescens, P. ni- 
gra and P. abnormis, Newm., the P. arenosa of Pictet i. In all other known 
species the sternal surface of each thoracic segment has on each side one or 
more tufts of these branchial filamentous appendages. Usually each tuft is 
formed of three bundles or packets of these simple structüres, into each of 
which a minute branch of a tracheal vessel is extended, and around which the 
blood circulates to be aérated. Pictet has shown that in the larva of Perla 
bipunctata, as also in other species, the middle one of each tbree tufts covers 
the future respiratory orifice or spiracle in the imago. A very similar form of 
tufted branchiz exists in Pteronarcys (figs. 3 & 4). 
The Pupa (fig. 2) of Pteronarcys regalis, the subject of the present commu- 
nication, was discovered by Mr. Barnston, who favoured me with a specimen 
of it, but it has not yet been described. It differs both in its general appear- 
ance and habit from that of Perla. It is of a dark olive colour, and is covered 
with slight pubescence. The head is short and triangular, with setaceous an- 
tenne, almost equal in number of joints to those of the imago. On the upper . 
surface of the head there are three rudimentary ocelli, and the eyes project 
* : 
: Monogr. Fein: des Perlides, pl. 53. fig. 7. + Loc. cit. pl. 11. figs. 7 & 8. 
1 See Postscript to this paper. 
