Graham Dixon Troubleatmill at
Sun May 31 04:41:30 EDT 1998


None of my regularly used Field-Guides seem to discuss the answer, to this
question, in any great depth.  However I have an old "COLLINS GEM GUIDE"
(Michael Chinery & Barry Hargreaves) that tries to throw some light on the

It says:-

One of the commonest questions asked about this group of insects is "What
is the difference between butterflies and moths?". It sounds a simple
question, but the answer is not a simple one, for there is no single
difference between all the butterflies on one hand and all the moths on the
other. Butterflies are almost entirely day-flying insects, while most moths
are nocturnal, but there are plenty of day flying moths and several of them
are brightly coloured and easily mistaken for butterflies.
It is often said that the resting attitude will separate the butterflies
from the moths: butterflies normally rest with their wings closed
vertically above the back, while moths generally hold there wings out to
the sides or roof-wise over the body. But there are exceptions: some
skipper butterflies, for example, hold their wings roof-wise over the body,
while certain geometrid moths, such as some thorns, perch with their wings
held vertically over the body.
The antennae are the best guide: all butterflies have small knobs on the
ends of their antennae, whereas moth antennae are usually thead-like or
feathery. But even this rule has its exceptions, for the day-flying burnet
moths have distinctly clubbed antennae and are regularly mistaken for
It is necessary to look at the wings to establish that these insects really
are moths. Look at the underside and you will find a slender bristle
sprouting from the 'shoulder' of the hind wing and running forward to
engage in a little clip on the front wing. This bristle is called a
frenulum and its job is to join the two wings and make sure that they beat
in unison. Many other moths have a frenulum, but none of the European
butterflies has one: in fact only one butterfly in the world - an
Australian skipper - is known to have a frenulum. Butterflies link their
wings together simply by having a large overlap.
Having said all this, it must be pointed out that the distinction between
butterflies and moths is quite artificial and unimportant. Most European
languages make no basic distinction between them; in French, for example,
butterflies are - papillons diurnes and moths are papillons nocturns. The
butterflies number less than 20,000 species and account for only 15 of the
80 or so families of Lepidoptera. All the rest are moths and they differ
amongst themselves just as much as they differ from butterflies.
The division of the order into butterflies and moths is therefor a very
unequal one as well as an artificial one

Obviously this is aimed at a British audience and as you "Colonial
Chappies" will appreciate, all our Moths & Butterflies have - Stiff Upper
Lips - Dress For Dinner - Hate to be referred to as LEPS and are
embarrassed when it comes to speaking openly, about sex. J

Graham Dixon

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