MR. TUFFEN WEST ON THE FOOT OF THE FLY. 397 



time, tlieir importance wotild seem to have been considered paramount. He compared the 

 Fly's foot with that of Dyticus ; but the superficial observations he made of the latter 

 go to prove that he cannot have used a magnifier of any kind in examining the great 

 Water-beetle ; or he could not have failed to observe parts (viz. the great suckers : to an 

 eye practised in minute observation, the whole set of small suckers as well) clearly enough 

 visible to the naked eye. His words shall speak for themselves. After simply saying, 

 " I might here name divers flies and other insects, who, bes.ides their sharp-hooked-nails, 

 have also skinny palms to their feet to enable them to stick on glass and other smooth 

 bodies, by means of the pressure of the atmosphere," he adduces the following proof of 

 the correctness of his explanation respecting the action of Flies' feet : — " But because the 

 example wUl illustrate another work of Nature, as well as this, I shall chuse a singular 

 piece of mechanism in one of the largest sorts of Hydrocanthari. Of these large ones 

 there are two sorts, one largest all black, with antennce handsomely embossed at the ends " 

 (SydrojyMlus). " The other somewhat lesser, hardly so black, with capillary autenncs ; the 

 forehead, edges of the vcigliice " (elytra), " and tAvo rings on the thorax, of a tawny colour " 

 {Dyticus marginalis). The female hath mgincs prettily furrowed; the male, smooth. 

 But that which is most to our purpose in this male is a flap, or hollowish cap near the 

 middle joint of the forelegs, which, when clapped on the shoulders of the female in coitu, 

 stiqks firmly thereon. And then foUows the comparison which, for want of duly weigh- 

 ing the value of the evidence, has misled, more or less, every succeeding author on this 

 subject : — " after the manner as I have seen boys carry heavy stones, with only a wet piece 

 of leather clapped on the top of the stone." 



Derham has not a word fm'ther on this head ! His observations and remarks evidently 

 possess no intrinsic value ; but it was necessary to ascertain distinctly what amount of 

 credit was their due, before proceeding further in our inquiry. 



Gilbert White (1788) * was no microscopist, and in writing on this subject he did but 

 repeat the prevalent opinion of his day. He was, however, a shrewd, painstaking observer 

 of facts in natural history, who noted the habits of flies as carefully as of the other 

 animals that came under his eye. And because a construction has been put upon his 

 words which was never intended by their author, and for another reason that Avill appear, 

 it is necessary just to see what he really did say on the present subject. 



Joiniag, then, in the general behef, he states that " in the decline of the year this re- 

 sistance" (the pressure of the atmosphere) "becomes too mighty for their diminished 

 strength ; and we see flies labouring along, and lugging then' feet in windows, as if they 

 stuck fast to the glass, and it is with the utmost difficulty they can draw one foot after 

 another, and disengage their hollow caps from the slij)pery surface." 



This paragraph, when connected mth one which precedes it, points to a very curious fact 

 in the Natural History of Flies. " As they grow more torpid " (through the advance of 

 cold weather) " one cannot help observing that they move with difficulty, and are scarce 

 able to lift their legs, which seem as if glued to the glass ; and by degrees many do actually 

 stick on till they die in the place." 



It becomes evident from the above that the temporary and voluntary attachment of 



* Natural History of Selborne, edition with Bennett's noteSj 1837, pp. 474, 475. 



3 h2 



