November 2, 1891. 



KNOWLEDGE. 



201 



^C^ AN ILLUSTRATED "^^ 



MAGAZINE OF SCIENCE 



SIMPLY WORDED— EXACTLY DESCRIBED 



LONDON: NOVEMBER 2, 1891. 



CONTENTS. 



Earwigs.— II. By E. A. Butleb 



The Mushroom. By J. Pentland Smith, M.A., B.Sc, &e. 

 Crocodiles and Alligators. By R. Ltdekkeh, B.A.Cautab. 

 On the Mass and Brightness of Binary Stars. By J. E. 



aoEE, F.E.A.S 



Letters:— T. S. Baebett ; T. E. Espix; T. W. Backhouse 



The Upper Atmosphere. By A. C. Ranyakd 



Notice of Book 



Meteorology of Ben Nevis. By Dr. J. G. McPheksox, 



F.R.S.E 



Birds and Berries. By the Rev. .\le.\. S. Wilso.v, M.A., 



B.Sc 



The London Basin. By Kdwabd A. Makti.n 



The Face of the Sky for November. Hy Herbekt 



Sadlee, F.R.A.S. 

 Chess Column. By C. D. Locock, B.A.Oxon 



203 



206 



209 

 210 

 212 

 2U 



215 

 2Ui 



218 

 219 



NOTICE. 



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EARWIGS.-II. 



1!y H. a. Butleh. 

 (('oiltinued fnnii pui/e ISli.) 



THE partiality of Earwigs for flowers, and imrticularly 

 for dahlias, has led to the adoption of \arious 

 devices in gardens to get rid of them, advantage 

 being taken of their fondness for dark corners. 

 Mouti'et, an old writer to whom we have referred 

 before, speaks of " ox-hoofs, hogs'-hoofs, or old cast things '" 

 as being set up in his time on sticks as traps by the 

 country women, to whom Earwigs, or erriwiggles, as they 

 call them, are exceedingly hateful, as he says, " because of 

 the clove gilliilowers that they eat and spoyl." Crabs' 

 and lobsters' claws have been used with effect in a similar 



manner. Into the recesses of these the Earwigs delight 

 to penetrate in the daytime, just as they have learnt to do 

 into the spurs of the tropieolum flowers (Fig. 4) since 



Fie. 4. — Tropifoliiin tlower, with Earwig in spur. Part of the flower 

 has been reiiioved. to disclose the Earwig. 



these were introduced into British gardens. But the 

 creatures are so ubiquitous, so abundant, at least in this 

 country, and so determined to skulk out of sight in the day- 

 time, squeezing themselves into most out-of-the-way places, 

 under stones, tiles, bark, leaves, or garden rubbish of any 

 kind, wherever there are but a few cubic millimetres of 

 breathing space, that it is next to impossible to devise 

 means which shall be very efl'ectual in reducing their 

 numbers. Not only do they damage flowers, but like 

 wasps, they are destructive to ripe fruit as well ; De Geer 

 fed some of those he kept with chopped apples, which they 

 eagerly devoured. Windfalls from the fruit trees in 

 orchards are soon found out and excavated by Earwigs, 

 which in the daytime curl themselves up in the hollows 

 they have made in tbe fruit, sticking close to their booty, 

 ready to fall to again as soon as the promptings of himger 

 and the return of darkness combine to render a banquet 

 desirable and safe. Though, as a rule, vegetarian in diet, 

 yet they have no objection to eating animal food if 

 opportunity serves, and as we have already seen, may even, 

 when hard pressed, resort to cannibalism ; but experiments 

 seem to indiciite tiiat they will be prepared to suSer great 

 extremities before falling back on such a practice. They 

 may be kept for a long time in numbers together, 

 without showing any disposition to attack one another, 

 even if the supply of food be scanty. They are not often 

 found indoors, Imt if accidentally introduced, may some- 

 times do irretrievable damage. The entomologist especially 

 has to be on his guard against them ; if they do manage to 

 gain access to his setting boards, they have no hesitation 

 in trying their jaws upon the insects that may be stretched 

 on them. The antenna^ of dried insects, particularly of 

 certain special kinds, seem to be peculiarly deUcate 

 morsels. The little booklousc, when attacking insects 

 moimted on card, u.sually makes for the antenme first ; and 

 the Earwig seems to have a similar taste. One collector 

 records that a single Earwig passed along his boards, and 

 in two days removed the antennii' from thirty-six moths all 

 belonging to one species, while examples of other species 

 were left untouched. The entomologist who hunts for moths 

 at night by smearing the syrupy liquid, technically called 

 " sugar," on the trunks of trees as a bait, often finds, on 

 revisiting his trap, that crowds of Earwigs have found out 

 the store, and are revelling in the tempting sweets. 



Hitherto we have spoken only of the Common Earwig 



