NATURAL HISTORY NOTES 
193 
their wings strongly, during which the tips of the latter are considerably depressed 
below the level of the thorax, I always thought it due to the rasping of the 
wing-rays on the under surface of the upper wings against those on the upper side 
of the lower wings. In all the butterflies of the Vanessid group the wing-rays in 
question are very strong and prominent, and I fancy I have noticed the same 
phenomenon in other species of the group. It will be observed that when the 
wings are depressed deeply the anterior or upper pair are brought forward till 
there is a decided gap between them and the posterior pair, extending almost to 
the body. I see no reason to think that this sound serves any useful purpose in 
the insect’s economy, unless it be in the nature of a scare ; for the butterfly will 
sometimes open and depress the wings suddenly on the approach of the collector, 
and the act might serve to intimidate small birds approaching with designs on the 
butterfly’s life. The conspicuous “ eyes ” on the wings would add to the effect 
by their sudden appearance. I have heard the common Tiger Moth ( Chelonia 
caia) make a somewhat similar noise when disturbed, and at the same time display 
the crimson “collar ” round its neck and exude a drop of yellow liquid on each 
side of the thorax. C. Nicholson. 
422. Insects and Floral Imitations.— I fear Knuth, as quoted by G. 
Henslow (400), was quite wrong in his notion as to the sight of insects. Butter- 
flies and moths are most easily deceived by even clumsy imitations of objects with 
which they are familiar. I have seen a specimen of the Silver-washed Fritillary 
( Argynnis paphia ) stop in his powerful and rapid flight to inspect a dead leaf 
resting on a frond of bracken, obviously because the dead leaf bore a superficial 
resemblance to that of the females of his species. It was some time before he 
could “ make up his mind ” that it was not so. Also, I have read of a Humming- 
bird Ilawk-Moth ( Macroglassa slellatarum ) which flew into a room and visited 
most of the flowers on the wall-paper, which happened to be of an unusually 
realistic pattern. The fact is, that insects have a broad perception of light and 
shade, a general idea cf colour, and a strong sense of smell, but their notions 
of form and distance are quite at sea, because the latter are of little account 
to them, while the former are all-important. C. Nicholson. 
423. Hearing' in Insects. The answer to Peter Ilastie’s query is that 
snails do not squeal when trodden on. The noise is simply due to the emission 
of air producing a series of minute bubbles, the rapid bursting of which produces 
the sound in question. I have not witnessed the painful process of boiling live 
lobsters, but suspect the cause of their “squeal” is similar. If they were abso- 
lutely plunged into fiercely boiling water, however, I should think death would be 
practically instantaneous, and so preclude any squeals. C. NICHOLSON. 
424. Ants. — The only way to effectually get rid of these insects is to find 
the nest and destroy it and all its inhabitants by pouring on boiling water, 
paraffin, a strong decoction of elder leaves or weak carbolic acid. If, however, 
the nest cannot be found, or conveniently got at, soak pieces of sponge in strong 
sugar-water or honey and lay them about where the ants are usually most notice- 
able. They will be attracted to the sweets, and when the sponges are well 
covered with ants, they can be dropped into boiling water, and then rebaited. 
This is a slow process, but perseverance will bring its usual reward. 
C. Nicholson. 
425. Clover Growing in Circles. -Was the grass mixture sown broad- 
cast? If so, the clover seed being heavier than the grass might be distributed in 
circular rings as the sower turned round in scattering the seed. The querist does 
not say whether the rings are impartially distributed over the lawn : if they are 
more or less confined to one part, it would suggest that the seed sorted itself in 
the bag before being sown. C. Nicholson. 
426. Plants on the Chalk. — I was much interested in “Plants on the 
Chalk,” No. 389, August, 1906. Last summer I climbed an iron-furnace refuse- 
hill, some acres in extent, near here. I found it covered with Viper’s Bugloss, 
although it is not found anywhere else in this locality. 
5, Fauy Hill Road, Kilmarnock. Wm. Birkell. 
August 15, 1906. 
