126 Mr. F. Merrifield’s Report of Progress in 
somewhat the appearance of a curled leaf with the con- 
cave side upwards. It would be interesting to know the 
position in which the other English species of the genus, 
viz., S. lunaria, rests. At first I fed the moths from 
little pieces of sponge dipped in very thin syrup, but I 
gave this up, as it seemed to promote mouldiness, and I 
do not think the moths lived any the longer for it. I never 
saw them feed, but had little time for watching them. 
When “‘nearly all”? the moths had emerged they were 
measured on their under sides, the wings being folded 
together over their backs. The length of the fore wing 
was measured from its tip or extreme anterior point 
(p in Mr. Galton’s figure, ante, p. 22). The other or 
shoulder extremity is not so easily ascertained or 
described, and at first the search for it gave me some 
difficulty ; but after a certain amount of practice I found 
that when a strong light fell obliquely along the wing in 
the direction from the tip towards the shoulder, it 
brought out a little dark transverse crease, in some 
cases shortened almost to a point, between the root of 
the hind wing (which, viewed from the under side, of 
course overlies the fore wing) and the body, and this 
crease I made my other terminus, taking the precaution 
of always laying the insect to be measured in the same 
position. This was done by fastening on the surface of 
a sheet of cork two strips of the same at about five-eighths 
of an inch apart, so as to leave a shallow flat groove of 
that width between them, and laying the moth on its 
side in this groove, a thin wedge of wood sheathed with 
zine being pushed along the groove so as to support the 
wings, especially their outer edges, and the wings being 
held down with the usual cork setting-bristle. A pair of 
screw-compasses was then taken, one leg fixed on the 
zine at the tip of the fore wing that lies uppermost, the 
other leg adjusted to the crease by turning the screw, 
and the length was marked off on a millimetre scale. 
The habit of the Selenias to bend their wings backwards 
when at rest facilitated the task, but I found chloroform 
indispensable ; applied in the form of vapour by a few 
drops on blotting-paper under a bell-glass just long 
enough to produce insensibility, it did not seem to hurt the 
insects in any way. The use of a pair of spectacles strong 
enough to bring my eyes to see clearly at five or six 
inches distance from the object was sufficient to enable 
