30 
THE ENTOMOLOGIST S RECORD. 
as compared say with Hadena chenopodii or Cucullia : the abdo- 
minal segments tapering, 5th and 6th being as usual free ; 
length ig mm„ width 5 mm., no hairs or bristles, though the 
double hairs at the antennal bases exist in little more than 
microscopic form. The sculpturing is in the form of very 
minute pits, which are most numerous dorsally, and do not 
exist on the leg and wing cases or thorax, which are finely 
wrinkled, but not so as to interfere with the shining polished 
character. ^ The transparency permits, especially on the abdo- 
minal segments, certain markings due to the interior structure 
to be seen, and including a darker dorsal line (dorsal vessel ?) 
a paler lateral one, with darker and lighter (fat masses ?) 
marbling between, the ventral aspect being paler. The pro- 
thoracic spiracle is a very slender slit, almost obsolete, indeed 
I am inclined to say that no aperture exists, those of the 2nd 
to 7th abdominal segments each being marked, being raised on 
a slight conical projection followed by a depression. The 8th 
abdominal spiracle is visible but obsolete. The anal armature 
consists of a wrinkled projection of the dorsal half of the 
extremity, armed dorsally by two central spines, and ventrally 
by three similar spines on either side. All this group have a 
similar armature, but vary, especially in the number of ventral 
spines on either side and in the curvature of the hooks, which 
they often form or terminate in. In tridens there is a very 
slight curvature, and the hold taken of the silk of the cocoon is 
slight. In tridens their number is very usually three, but a 
considerable proportion of pupae have four, or, not unfre- 
quently, four on one side only. When this occurs, the extra 
spine is often very slender and close to the outer side of the 
outer one, as if split off it. It is curious that the name tridens^ 
given no doubt on account of the trident or psi mark of the 
imago, should be so applicable to this typical point in the 
pupal structure. The curvature of the ventral set is inwards, 
of the dorsal pair downwards (ventrally) more decidedly than 
the others (see PI. III., za, 2b, 2d). Certain flattenings of the 
dorsal surfaces of the first four abdominal segments, which are 
more evident in some other species, are easily observed in this 
species when carefully looked for. 
To form its cocoon this species appears to prefer to get 
behind a piece of loose bark or into a chink of rotten wood, 
where it hollows out a suitable cavity, which it completes into 
a cocoon with some white silk and the removed chips, very 
slightly, if at all, lining the excavated hollow. It will, however, 
