June 5, 1885.] 



♦ KNOV/LEDGE 



473 



that the i-ays from the star will be carried by the Jt Hooting 

 power of that hii/er, along some particular direction, and 

 unless the eye be exactly on their coui-se, those rays would 

 not make the star visible. But the eye selects the particu- 

 lar pencil of rays coming to it, and sees the star in the 

 corresponding direction. 



In conclusion, let me again point out that I a:u not 

 advocating any theory, speculation, or conclusion of my 

 own, but simply endeavouring to remove an objection 

 which has been raised (through misapprehension) against 

 the true explanation of the ruddy eclipsed uioon, — an ex- 

 planation accepted by all who are sutliciently acquainted 

 with optical principles to examine it understandingly. Of 

 Mr. Williams's speculation about the moon being red hot, 

 I simply say that while it apjiears to be disposed of by the 

 entire blackness of the moon during some total eclipses, it 

 certainh/ cannot be supported by such reasoning as he has 

 based on misapprehension of the accepted interpretation of 

 the ruddy-eclipsed moon. But I do not feel in the slightest 

 degree anxious to galvanise it into apparent life by 

 attacking it. 



OUR HOUSEHOLD INSECTS. 



By E. a. Butler. 



COLEOPTEKA (coniinued). 



'WJ'E- now turn to another family of beetles, the 

 T V Dermestido', a group of small extent, but of most 

 destructive habits. One of them (Fig. I.) har, rendered 

 itself sufficiently olmoxious to have acquired a popular 

 natue, the " Bacon beetle," a designation which indicates 

 not a necessary association, but merely a casual one, which, 

 however, h.is, more than any other, brought the insect 

 under the notice and reprobation of human kind. In 

 scientific language it is still called by the name under 

 which the great Linnc wrote of it in his " Systema 

 Natnr.-e," viz., Derrnestcs lardarius, the second word of 

 which is an almost literal translation of the popular name. 

 The generic title Dermestes is from the Greek derma, a 

 skin, and indicates that the tastes of the insect lie not only 

 in the direction of fat bacon, but equally in that of tough 

 leather. 



Fig. 1. — Dermestes lardarius. 



It ia a ])arallel-sided convex, rather elongate insect, about 

 \ in. long, and may be at once recognised by the yellowish- 

 grey band which sweeps right across the elytra, occupying 

 almost the whole of their basal half {i.e. the part next the 

 thorax), in sharp contrast to the Vjlack of the remainder of 

 the body both before and behind ; the two colours meet 

 abruptly in a well-defined, somewhat wavy Vwundary line, 

 running across from side to side. In the present order it 

 very frequently happens that, as we have already seen in 

 Niptus, the colours that appear on the surface are not in- 



grained into the skin of the insect itself, but are produced 

 by hairs or scales with which it is more or less thickly 

 coated, and it is not until these have been removed that 

 the true colour.^ of the body, which do not necessarily cor- 

 respond with the superficial ornamentation, can be clearly 

 ascertained. The present insect is covered toleiably thickly 

 with hairs, and the parts tliat are superlicinUy black aie 

 also of tiirtt colour when denuded of their covering, but 

 under the pale patch the elytra are of a very flrep reddish 

 brown. 



The head is of small dimensions, and, when the insect is 

 at rest, is carried bent down beneath the thorax, a position 

 from which, in a defunct individual, the coleoptorist who 

 desires all parts of his specimens to be properly displayed, 

 finds it no easy matter to coax it out. The antenn;e are 

 ot the type known as clubbed, a feature which indicates 

 that the insect belongs to that large section of the beetle 

 order called Clavicornia, or Club-horns, a group containing 

 about 600 Britibli species, a good many of which art; 

 feeders upon carrion and the dried carcasses of other 

 animals. A clubbed antenna is usually almost abnormally 

 short, and may bo at once distinguished by the fact that 

 the terminal joints, two, three, four, or five in number, are 

 much broader than the rest. It is surprising how many 

 varieties this very simple peculiarity is cajuble of, and 

 these variations are of much importance in the systematic 

 arrangement of the insects. In our present species, the 

 club consists of three flattened joints, broadened inwardly 

 only, whereby it acquires a one-sided appearance. 



The legs are of moderate length, and are packed up 

 under the body when their owner counterfeits death, as it 

 very readily does on the slightest alarm, being, as well 

 becomes so inveterate a i)ilferer, of timid and retiring 

 habits. But this folding up is not so perfectly carried out 

 as in many other insects, for the last section of the limbs — 

 viz , the five-jointed tarsus, or foot, is not folded back upon 

 the preceding part, or tibia, but simply brought up so as to 

 make an angle with them. 



The larva of Dermestes is something like a very hairy 

 caterpillar, and is no connection of those lively maggots 

 that al.so infest bacon, and whose acrobatic feats have 

 earned for them the name of "jumpers ;" it casts its skin 

 several times in the course of its life, and on account of the 

 multitude of hairs (which are shed with the skin and 

 renewed each time), the rejected vestment does not shrivel 

 up, but retains the form of the larva, a very substantial 

 ghost ot its former self. 



We possess five British species of this genus, all of 

 which are essentially devourers of skins and dried carcasses ; 

 in fact, they are the jackals of tlie flesh flies, coming round 

 when the maggots of the latter have finished up all the 

 soft and juicy parts of a fresh carcass, and clearing ofi' the 

 hard and dry remnants of the skin, tendons, ligaments, &c , 

 which their predecessors have left untouched. This is 

 their natural function in the economy of nature, and when 

 man also accumulates stores of dried meats, skins, feathers, 

 horns, and hoofs, it is not to be wondered at that they 

 forsake the scanty and precarious provisions of dame 

 Nature, and invade his precincts who has so thoughtfully 

 laid up such grand stores for thsm. 



Some years ago, D. riilpimis, a black species with a 

 white patch on each side of the thorax, swarmed to such a 

 degree and was so destructive in large skin warehouses in 

 London as to bring forth the handsome offer of a reward 

 of £20,000 for an available remedy. But satisfactory 

 remedies against the ravages of in.sect3 are usually difficult 

 to discover, and difficult also to apply, and it is uot alto- 

 gether surprising that even so tempting an offer failed to 

 secure the desired result. The curators of museums, too, 



