RAVAGES OF HOUSE MOTHS

Otago Witness, Issue 3958, 21 January 1930, Page 7

RAVAGES OF HOUSE MOTHS

By Professor J. Arthi r Thomson. Sonic insects are beneficial, such as bees and silkworms; some are altogether injurious, such as those mosquitoes that carry the malaria organism and the tsetse Hies that carry the cause of sleeping sickness.. But most insects are half and half, partly helpful to man and his interests, and partly prejudicial. Thus, if we consider wasps in a broad way, we must admit that while they spoil a lot of fruit, they destroy many insects that aie pests of plants. While the world of life is on the whole “ friendly” to man, we need not expect it to be always on our side. And as re- I gards particular insects, such as earwigs, I it is often impossible to get a true bill, for there is a “ con ” to every “ pro.” So we turn with mental satisfaction to clothes moths, for they are altogether on the black list except to the naturalists. who find them very interesting. 1 '■>' • ■ I kroaches. they have linked themselves to man. for unlike the casual b-uyi.-h mollis which come in at tin- open window of an evening and are fatally compelled to fly into the lamp, the true clothes moths are always with us. ami do not visit the outer world at all. They have doubtless evolved from near relatives that feed on lichens, bark, and so forth in the open country. I rue clothes moths are species of linea. iu the group Tinea*, among which are the smallest of all the small moths. There are over two dozen species of Tinea in Britain, but only three or four of these have become permanent foes in I man's household. A very common species, especially in j summer, is Tinea pellionella, about half . an inch across when its wings are fully ‘ spread. if we could forget the catcri pillar's depredations, we should call the I moth beautiful, for its fore-wings are I shining greyish yellow with three vague | brownish spots on each, and the hind- ; wings are whitish grey. It does not eat ; at all; that is the duty of the tiny cateri pillar, which has a dull whitish body I ami a reddish brow n head. j Peculiar and admirable is tiie tunic or ! ease with which it protects itself as it I roves about among our precious fins. ; I he outside of the case is fashioned of i fragments of hair or fabric; the inside ! is. lined with soft silk which the cater- ’ pillar secretes from behind its mouth. < The case is open at both ends and varies ■ of course in colour and texture according I to which of our garments the caterpillar i has been corrupting. At one end we ; can see the head and three pairs of loco-

motor limbs sticking out. while the posterior pro-legs serve to grip the inside of the ease. When we shake the fur coat, the caterpillars retire completely within their cases. As they feed they have to moult their outer husk or cuticle, and they haw also to add to their ease. This they do at both ends, for they are actually able to turn right round inside their tube. When it is full grown, tin? caterpillar becomes a chrysalid inside the case, a little yellowish-brown oval, and before it passes into quiescence it fastens each end of the case by silk threads to the fabric or to the sides of some safe crevice near by. In about three weeks there emerges the moth, soon able, as we know, to 11 v ami run quickly. Its hunger is over: its business is to get mated. In furs and feathers the mother lavs the minute eggs, and out of these come the htmgrv caterpillars. Another common clothes moth, rather larger than the ease-bearer, is the Tinea, biselliella. Ihe fore-wings are shining yellow without spots: the hind-wings are. paler: the head is reddish. Instead of making a portable coat, this caterpillar constructs a fixed tunnel in the fabric Into this it retreats when disturbed, an I within its shelter it becomes a brownish mummy-like pupa, wriggling uncannily when disturbed. The caterpillars am. busy iu the summer months, and will eat woollens, such as flannels, as well as fuis. Larger still, with a wing span of about three-quarters of an inch, is the tapestry moth. Tinea tapetzella. The fore-wing-: are black basally. then mottled creamy white: the hind wings are shining brownish grey with long fringes. When the moth is resting, the hind-wings are quite hidden, and the insect appears as a long narrow object, black in front and white behind. The caterpillar devours coarse fabrics like carpets, and it makes no ease or tunnel, smply lining its burrowed galleries with its own silk.

These are the three commonest clothes moths, but there are relatives to which the loose popular term is sometimes applied. Some of the larva? have discovered strange niches of opportunitv, thus there is one species of Tinea that occasionally devours the sheaths of the horns of living antelopes! Most of the Tinea? show this predilection for horn—a strange dietetic specialisation. Hairs and feathers are. of course, made of horn or keratin, just like our fingernnrls.

Very precious furs should be wrapperl up in paper with no loose ends, for th? moth cannot get through patier. We have known of the skins of small mammals being entirely protected, for over a score of years, inside wisps of thin paper.

It is also useful to have balls of nap thaline or camphor or tin like among

the furs and clothes, for the moths ar.* repelled by the odour. When the tiny caterpillars have got a footing, exposure to fresh air and sunshine often effe'ts a speech' clearance.—John o’ London's Weeklv.'