MR. TUFFEN WEST ON THE FOOT OF THE FLY. 411 



A few words will describe all that need be said, in tbe present place, respecting some 

 modifications of tenent hairs for sexual purposes. 



An example is given from Amara (fig. 22), to show that there is no essential dif- 

 ference between these and the large tenent hairs which have just been described at 

 length, other than as relates to their size ; in their number, 1-11 on each hand, the two 

 entirely agree. They are arranged thus : on each side of the first tarsal joint, 2G ; of the 

 second, 26 ; of the third, 20. Greater diameter of the membranous expansion of a large 

 one, -002 inch; entire length of shaft, -008 inch. 



The next example, from the hand of the male Carabus graniilatus (fig. 23), possesses 

 an especial interest from the features which it presents, in relation both to the size and 

 to the number of the tenent hairs*. In size they stand about midway between large 

 and small ; diameter of expanded part, which is orbicular in outline, '0007 inch ; extreme 

 length of a tenent hair from this beetle, -0055 inch. Speaking of their number, it may 

 be said that they are very numerous; I have not yet counted them. They arise from 

 the first three joints only of the tarsus. Towards the free end, for half their extent, they 

 are greatly corrugated, just like stiff leather, as a strap, when much bent about, becomes 

 covered with transverse wrinkles. This corrugation is present on all tenent hairs destined 

 for sexual purposes ; observations on the habits of the beetles possessing them satisfac- 

 torily account for the appearance, and prove that the mode of its formation is as above 

 supposed. When in the live-box, beetles having such appendages to their hands press 

 them firmly against the glass cover, and then, upon these as fixed points, the body is con- 

 tinually swayed about in every direction. And whoever has observed the males of the 

 large Carabi attached to their mates in copula, by whom they are di'agged about in stony 

 or gravelly places, will see that the rude shocks to which these tenent hairs must be con- 

 stantly exposed, under such circumstances, will readily account for the corrugations 

 described, on parts having a leathery texture. 



Amongst the Staphyliuidse, the " anterior tarsi " are " often dilated in the males f." The 

 tenent hairs for sexual purposes are often very well developed ; in some species they are 

 very numerous, in others very few in number. Where present, they are of a softer 

 texture than those last named, so that indications of corrugation are but very slight. In 

 Ocypiis olens (fig. 21) and Creopldlus maxillosus, the tenent hairs form a dense cushion 

 on the under-surface of the four basal joints of the anterior tarsi. Their free ends are 

 especially soft, so that it is difiicult to say what should be considered their real shape. 

 When viewed in action, from the closeness with which they arc packed, they have a ten- 

 dency to assume a form varying from orbicular, even to slightly hexagonal ; when dragged 

 over the glass they become lengthened into oval, elliptic, and fusiform shapes. "K. Beck 

 has noticed that the expansions shrink and almost disappear when these insects are j)laced 

 under the influence of chloroform : this I had not myself noticed ; but the almost complete 

 disappearance of the expansions in dead specimens is satisfactorily accounted for by it. 

 On the upper surface of the expansions, in the two examples above named, there are some 



* "CARABiDiE." "Anterior tarsi greatly dilated ia the males." — Webtwood, Introd. vol. i. p. 89. 

 •f Ibid. vol. i. p. 163. 

 VOL. XXIII. 3 K 



