404s MR. TUFFEN WEST ON THE FOOT OF THE FLY. 
Mr. John Hcpworth (1854) * also, nearly at the same time, and in near neighbourhood 
with the last-named author, was repeatedly examining the feet of some large flies, and 
other insects, in the living state. The terminal enlargements of the " hair-like appendages" 
were now for the first time clearly represented : their mode of action is compared with that 
of the suckers of the male Dyticus. The general form of the flaps, their thickened base, 
and thinned-out margins were described from several flies, as they appear when viewed 
under the compound microscope. The scale-like hairs occasionally found on their upper 
surface are also noted, as well as, from independent observation, the marks left on glass 
by the " trumpet-shaped extremities of the appendages to their flaps." A portion of the 
edge of the flap, which had got turned in mounting, " is figured," which shows the s ackers 
more distinctly. 
The descriptions are brief to a degree which renders it difficult sometimes to understand 
the exact meaning of the author ; this is, however, remedied, in some degree, by the 
abundance and general clearness of the illustrations ; in remarking on which, we are told 
that "the parts are too obvious to require description " (!). 
Mr. Hepworth's opinions possess much value because they were founded on independent 
observations, with the microscope, on the parts as they appear during life, in action and 
in repose, and were repeated frequently and with care. 
Mr. Tyrrell (1855) f suggested the use of the " hooks on the feet of flies," as " intended 
not to attach the fly to anything, but to be used as fulcra or props which the fly can push 
against when it wishes to detach the cushions." Careful investigation proves that they 
used for the purpose of detaching the foot ; but it was a very imperfect view of the 
matter to think that this was their only use. 
Mr. Hep worth (1855) | in replying to remarks, in continuation of the above, which 
evince a misapprehension of his views, takes occasion to go into some detail respecting nis 
opinions. He says that each sucker is under the influence of the will, and adduces some 
valuable observations by Ecker, on contractile structures in their earliest manifestations, 
as representing exactly what he wishes to express in this matter. An objection to the 
viscid-secretion theory, when carried to the excess it was by some of its advocates, and 
which will readily occur to the student, is well put. " If," he says, "the foot were 
to be attached for some time (twenty or thirty minutes, as I have often seen it) to the 
same spot, it would get so firmly fixed that, if forcibly raised by the leverage of the hooks, 
these exceedingly delicate structures" (the "hair-like appendages") would be destroyed. 
A computation is then given of the number of " suckers " on " the flap of the Blow-fly, 
which I believe to be correct when the number allowed for " the triangular part, extending 
for attachment up to the leg " has been deducted. This deduction is necessary because none 
of these organs are present on a part which can never be applied to any surface for the pur- 
pose of holding to it ; with this allowance, the number will be about 12,000 on each foot 
of the fly in question. The paper continues, by explaining a " diagram," of " Hairs from 
the pad of the foot of a small Curcidio beetle ; they expand into the form of a trumpet, and 
where the expansion commences they appear corrugated, and the corrugation is continue 
* 
t 
Journal 
t Ibid 
