May. 1002.] 



KNOWLEDGE 



07 



ILLUSTRATED MAGAZINE 



-^lEN€EJLiTERATURL4^fr 



Founded by RICHARD A. PROCTOR. 



Vol. xxv.J LONDON : MA V, 1902. 



[No. 199. 



CONTENTS. 



stilt-Walkers. By K. A. Uctlkk, b.a.. b.sc. {Ilhisiraled) 

 The Ancient Wild Ox of Europe, and its Living Repre 



sentatives Bv K. Lyi>kkkkk 

 Astronomy without a Telescope. XIII.— A Modern 



Tycho. B,v K. WAtTKE SlArxDER, F.E.A.8. (UliislrateJ) 

 Clouds. By Coiiimandpr D. Wilson Bahkkr. r.n k., f.h .-i.K.. 



r. H.MlT.soc, cto. Illittlraled) 



Clouds. Kull-)Mgc Plate illiii-trating Squall CrMur.us, Tillab 



t'CMCLCS, ClBBUS, Ultill SnUTUS and Cf.Mri.CH. 



Letters : 



FvHRKxnKiT's TiiKHMOMETER. By Clevkland Abbe ... 

 The VisiBiMTT of the Crescext of Vkmus. By B. P. 



Sei.bt. Note by E. Waiter Mattndeb 



Tub Vi-'IBilitt of the Crescext ok Ykxcs. Bv Jamks 



RoHOKK 



British Ornithological Notes. ComUictod by \V. P. 



PvCBAFT, A.L.S., F.Z.8., M.B.O.T 



Notes 



Notices of Books 



Studies in the British Flora III. — Ferns. By R. 



Llotd Prabobb, B.A. (IlluHrated) 



Microscopy. Conducted by M. I. Cross. {Illustrated) ... 

 Notes on Comets and Meteors. By W. F. Denniko, 



F.B.A.9 ... 



The Face of the Sky for May. By W. Shackleton, 



F.B.A.9 



Chess Column. By C. D. Locock, b.a 



109 

 109 

 110 



no 

 111 



112 



113 



117 



STILT- WALKERS. 



By E. A. Butler, b.a., b.8c. 



The order of insects which is known as KhvnchotH 

 (beaked), or Hemiptera and Homoptera, and popularly 

 called "Seld-bugs." contains many extraordinary forms 

 remarkable for the extreme modification to whicii one or 

 more of the organs of the body have been subjected. 

 Some i>articular line of development has been followed to 

 such an extent that it seems impossible to imagine any 

 flirt her mo<lification in the same direction ; the climax has 

 been reached, and the jmssibility of any advance beyond it 

 seems to l>e barred by the mere physical conditions of 

 existence. The parts that possess the greatest plasticity 

 appear to be the thorax, the legs, and the antennsc. 

 While the most noteworthy devehipments are seen, as 



might be expected, in exotic species, our own country 

 furnishos in this order at least one small and interesting 

 tollcciion of insects exemplifying a tendency of the kind 

 referred to. From different families of" the British 

 Hemiptera we may select a group of species which have 

 attained in their legs and antennae the highest degree 

 of length and tenuity that seems compatible with the 

 preservation of these organs at all. Of course a consider- 

 able reduction in the thickness of the body has been 

 brouglit about at the same time, otherwise it would have 

 been too lieavy to be supported by the attenuated legs. 

 As these examples belong to several distinct families, it is 

 evident that their slenderuess has been independently 

 acquired, and hence wo have in these stilt-walkers a good 

 instance of iiarallcl development. Since the insects are 

 absolutely unknown to any but professed entomologists, 

 they have no popular names, and hence, in speaking of 

 them, I am compel leil to use their somewhat cumbrous 

 scientific names. 



As the first exain]ile of this spectral group we will take 

 the insect calle<l Mf/atropis riifi'nceni! (Fig. 1). This is by 

 no means a common insect, though when it does occur it 

 can usually be found in some nuinijers. It is a vegetable 

 feeder, and is sjiecially attached to the plant called 

 "Enchanter's nightshade" (Cirriea lutetiana), the juices 

 of which it sucks through its slender beak. The plant is 

 an abundant weed in shady places, but the insect is not 

 more tliau a very occasional accompaniment of it. It is 

 an exceedingly elegant sj)ecies, witli a narrow body of a 

 reddish yellow colour, about five-eigliths of an inch long. 

 The thorax rises into a strong liump behind, and is 

 ornamented and, no doubt, strengthened with three 

 prominent keels, like buttresses, one in the middle and one 

 at each side. Behind the thorax the body suddenly 

 narrows and shows a pinched-in waist. The thighs of all 

 the legs are swollen at the tip, or, in other words, end in a 

 club. Tliis is also the case with the first joint of the 

 artenna?, while the terminal joint is wholly swollen and 

 club-like. These clubbed thighs and antennse are entirely 

 characteristic of the family to which the insect belongs. 

 All these appendages are pale-coloured, and their whole 

 length is thickly spotted with black. The legs end in very 

 small feet, each of which, notwitlistanding its minuteness, 

 consists of three joints, and these six minute objects are 

 the only parts that are in contact with the ground. 



Such is th_' insect which may be found in late summer 

 standing on. or walking over, the leaves of the enchanter's 



Fig. 1. — Metatropis rnfescens. Fio. 2. — Mefacanthti.f punrtipes. 



nightshade, keeping its body well up off the leaf, slung up, 

 as it were, on its six hair-like legs, which act as so many 

 springs. The antennae, being so much like the legs in both 

 shape and adornment, give the insect the appearance of an 

 eight-legged creature such as a spider, though the length 



