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HARDWICKE'S SCIENCE-GOSSIP. 



envelop it in a piece of cloth, with the intention of 

 conveying it to his cabinet. On his way thither, how- 

 ever, he had occasion to examine the interesting speci- 

 men, and his surprise may be better imagined than 

 described when he perceived a young beetle, resem- 

 bling in every way the larger insect, except that it 

 was smaller, emerging from its dead parent's body. 

 Mr. White kept the live beetle under a glass for five 

 months and before it died at the end of that period, 

 to paraphrase the old song, so young and yet so old, 

 it seemed to be thriving, and had perceptibly 

 increased in size. The larger insect, in its iron cyst, 

 and the younger beetle, which was indubitably 

 generated in prehistoric times to be born in ' this 

 wonderful nineteenth century,' may be inspected by 

 all who should happen to be in the vicinity of the 

 district mentioned." — F. C. Bing. 



Query as to an Algerian Insect. — I send 

 herewith some sketches of parts of an insect which 

 committed suicide on my lamp a few nights since, and 

 as it was a stranger to me I examined its mutilated 

 remains, and found them sufficiently curious. I 

 suppose it is a saw or ichneumon fly, but am not 

 entomologist enough to identify it, and have no 

 reference library available. I shall be glad if you 

 can name it and shortly state what may be known of 

 its life-history and relations. Its total length was 

 barely \ in., colour light sandy-brown, lower wing 

 longer and narrower than upper. No hooks were 

 seen on the wings, but they were much mutilated, 

 especially the lower ones. The nerves of the upper 

 wings presented a curious knotted appearance under 

 a low power, under a higher one the " knots " appear 

 to be vesicles or hair bulbs, or possibly perforations 

 in the membranes. The nerves of the lower wings 

 are without any trace of these knots, but are of 

 irregular outline, and in both wings the nerves are of 

 dark brown colour, while the membrane seems 

 structureless and colourless. There was only a slight 

 reticulation on the upper wing to represent the 

 " stigma." The edges of both wings present a very 

 regular imbrication or scalloped appearance, finer in the 

 lower than in the upper wing, and in the former only 

 each scallop terminated in a very fine point or hair. 

 The upper wing showed no scalloping on the outer 

 margin until reaching the stigma. The minute hairs 

 were more plentiful on the lower than the upper 

 wings, as shown. The posterior legs showed some 

 curious spurs, especially a comb of 19 teeth projecting 

 from the lower joint of the tibia. Anterior legs were 

 free from these spurs, but hairy. Middle legs could 

 not be found. The antennae are very curious, a short 

 hairy first joint, which lies in a niche or depression 

 nearly cutting the compound eye into two parts, the 

 second joint short, club-like, carrying several circles 

 or crowns of erected papilla?, with fine long bristles 

 inside and outside the circle. Attached to the 

 extremity of this point by a transparent ball, ap- 

 parently, is a long bristle of 13 or 14 joints, the first 

 being bulbous, and the remainder much thinner, 

 tapering slightly and irregularly, colour dark, joints 

 marked by transparent transverse spaces. The 

 ovipositor retracted lies entirely inside the abdomen. 

 Its sheaths are dark, and very finely serrated near the 

 tip. The internal spear carries rounded teeth well 

 spaced, somewhat like those of the lancet of the gnat. 

 Are they for cutting animal tissues too?— Henry M. 

 Sayers. 



A SINGULAR freak of nature was to be seen a few 

 days ago in one of the gardens between Northgate 

 Street and the river. A young apple-tree (Lane's 

 Prince Albert) planted last autumn had been con- 



siderably cut up by the frosts, and only bore one 

 apple. At the end of the twig upon which the fruit 

 hung there was, however, a handsome bunch of 

 blossom. Ripe strawberries have also been picked, 

 both at Canterbury and Ashford within the past few 

 days. — Kentish Gazette, Canterbury. 



Our "Exchange Column" and how it is 

 used. — The following appears in a leading Scotch 

 paper : — 



Owls and Mice.— The following advertisement, 

 cut from Science Gossip, is pertinent to the subject of 

 the recent correspondence in your columns. — "For 

 exchange, a number of long-eared owls' eggs. 

 Wanted, Norfolk plover, nightjar, petrels (leach and 

 fork-tailed), raven, oriole, or any of rarer hawks. 

 Also several clutches of common sand-pipers' eggs. 

 Wanted in exchange, dunlins, redshanks, jays, bull- 

 finches ; other offers considered. The eggs are all 

 side-blown, and taken by me here this season. — 

 R. Armstrong, B.A., Thornhill, Dumfriesshire, 

 Scotland." You will observe that Mr. Armstrong's 

 industry is carried on in the very heart of the vole- 

 infested district. — Herbert Maxwell. 



The Limpet's Adhesive Power. — Dr. Lawrence 

 Hamilton, of Brighton, writes in "Natural Science" 

 as follows : — Having previously ascertained by a 

 series of experiments, made at Folkestone in June, 

 1889, the force necessary to overcome the great 

 powers of adherence of the limpet (or upwards of 

 1984 times its own dead weight, allowing for the 

 limpet being deprived of its shell), I determined to 

 make another series, in order, if possible, to find out 

 the source of these remarkable natural adhesive pro- 

 perties. To do this, I placed several limpets on the 

 side of an empty glass tank ; I then drilled two holes 

 through different rings in the top of each shell, and 

 passed through them a stout copper wire. The ends 

 of this wire were twisted together, and then attached 

 to a spring balance. By pulling on the latter, the 

 force necessary to detach the limpet could be readily 

 observed. Owing to the glass plate, it was easily 

 ascertained that no air-space existed beneath the foot, 

 which in every part was in close contact with the 

 glass. On exercising slight traction on the limpet, 

 the foot and mantle became still more closely applied 

 to the surface of the glass. On injecting the limpet 

 with corrosive sublimate, more than sufficient to 

 immediately destroy all vitality, the shell became 

 quite loose, but still the foot remained adherent. 

 The force necessary to detach the dead limpet was, 

 however, very much less than in the case of the 

 living, for whilst a force of 35 lbs. was required to 

 remove the living limpet, 25 lbs. sufficed to displace a 

 limpet immediately after poisoning. Twenty-four 

 hours after death a force of 9J lbs. was required to 

 detach the limpet. When the limpet was dislodged, 

 a thin gelatinous coat remained on the glass wall ; 

 this substance appeared only slightly soluble in sea- 

 water. From the above experiments, we may, 

 perhaps, be justified in concluding that while some 

 portion of the adhesive power may or may not be due 

 to atmospheric pressure, a very considerable amount, 

 if not the major part, or perhaps all, is probably 

 dependent upon the throwing out of a very tenacious 

 substance. In favour of the latter view is the 

 definite evidence of the absence of a vacuum beneath 

 the foot, or of any mechanism whereby such a 

 vacuum might be produced, such for instance as is 

 seen in the suckers of the tentacles of octopi, &c, 

 and the fact that the adhesion continues after the 

 death of the animal, as well as the positive proof of a 

 tenacious secretion. In these experiments the shell 



