VAlllATIOX. 
155 
females are on the wing ovipositing, etc., and we get no real idea of 
how much their wings are used. Whoever captured a ^ Bombyx 
quercus on the wing late at night ? I have taken dozens of females in 
this way. But Mr. Arkle leaves out of sight the probable reason of the 
larger wing area generally found in female moths where both sexes are 
active. I refer to the extra weight of the body when distended with 
ova which the females have to carry. The examples quoted by Mr. 
Arkle might be increased tenfold, and as a rule the greater the 
difference in the weight of the body in the sexes, the greater the 
difference in the wing area. Lasiocampa quercifolia is a case in point. 
Where the bodies of males and females are almost of equal weight, the 
wing area is much the same. This would more than counteract 
“the greater use in the males” if there be such greater use, which I 
much doubt. — E d.] 
Varieties of Zyga:na filipendula: and Z. trifolii. — Whilst 
collecting in the Isle of Wight, this year, my wife found on some 
undercliff a colony of Z. filipendidcB^ and amongst them the yellow 
variety. We visited the spot on several occasions after this and were 
fortunate enough to find two more specimens of this variety, all of 
them without the faintest tinge of red in the yellow ; although we 
examined hundreds of this species we failed to find any other varia- 
tion. I also found in a damp meadow Z. trifolii abundantly, the 
type of which was scarce ; the majority had the two spots in the centre 
of the wing coalesced, and in many, the five spots were joined and 
formed a brilliant splash. In both species I noticed that the larvae had 
spun up in an apparently haphazard way, choosing whatever object 
came first, such as stems of various plants and thistle leaves, and many on 
an adjacent boathouse. — P. W. Abbott, Birmingham. August^ 1891. 
With further reference to the occasional occurrence of the yellow form 
of Z, filipendul(E^ I was fortunate enough to find one myself on July 20th 
in the same locality referred to by Mr. Abbott in the preceding note, viz.^ 
a rough grassy undercliff, near Brook, in the Isle of Wight. The species 
was excessively abundant, and the few thistles scattered throughout the 
undercliff were simply a mass of “ Burnets/’ and whilst in some spots 
it was difficult to find a suitable grass stem without a cocoon attached, 
yet these were not confined to the grass stems, as many dozens were 
spun up on the boathouse Mr. Abbott mentions, and others on a small 
windlass close by. In one case a second cocoon was made almost over 
the first on a grass stem, but not enough so to interfere with the proper 
emergence of the imago ; whilst in the case of Z. trifolii, in another 
locality, the cocoons were distributed in quite as erratic a manner. I 
found several on large rush stems, and one on the underside of a broad 
leaf of Iris. With reference to Z. filipendulcz, I may say that, althougli 
I have worked the same spot for several seasons, I have never seen the 
species in anything approaching similar abundance, nor have I met 
with the yellow variety before, of which, unless my memory deceives 
me, Mr. arid Mrs. Abbott secured four specimens, one of which they 
very generously added to my collection. They also succeeded in 
