Oct., 1889. 
THE FUNGI OF WARWICKSHIRE. 
225 
be shown in a darkened room, by attaching a small piece of 
glowing charcoal to it. A small piece of gold leaf fixed with gum 
to the ton of a flv’s wing describes a similar curve. In order 
that an insect may advance through the air, the position 
of the wing surface, when not bent aside by the air, must be 
altered from a vertical plane to one sloping upward and 
forward. This might be accomplished by the whole insect 
assuming a more horizontal position, or by a change in the 
position of the wing itself, which might or might not be 
accompanied by a change in its motion. The observation of 
the change is very difficult, as the insect moves forward 
instantly when it takes place, but I incline to the view that 
the only alteration is a rotation of the wing round its stiff 
edge, so that it slants downwards and backwards from this 
edge instead of hanging merely downwards. In any case, it 
takes this position, and two distinct and independent results 
immediately follow. First, the pressure against the air being 
now directed downwards and backwards instead of merely 
downwards, the insect is urged forwards as well as supported 
by the motion of the wings. This would be the case just as 
much even if the insect’s bodv was fastened so that it could 
«/ 
not really move forwards. But besides this, the wing surfaces 
having on the average this upward and forward slant, the 
forward motion of the whole insect through the air causes 
them to tend to rise quite independently of their vibrating 
motion, so that there is a second supporting force which 
would still exist even if the insect ceased to move its wings, 
if only they were outstretched and the forward motion of the 
whole insect continued. I must be excused if I insist rather 
wearisomely on this point; it is a very important one, for it 
is by the development of this second and supplementary means 
of support that a method of flight is arrived at which is 
available for larger animals, and we have the possibility of 
the bird. 
(To be continued.) 
THE FUNGI OF WARWICKSHIRE. 
BY W. B. GROVE, M.A., AND J. E. BAGNALL, A.L.S. 
Sub genus XXVII.— Crepidotus. 
(Continued from page 193.) 
247. Ag. mollis, Sckaff. On logs. Aug.-Dec. On the foot 
of a bridge, in the black lands (Ipsley), Purt., ii., 659. 
Hopsford, near Brinklow, Adams. Warwick, Per cecal. 
Solihull, Hawlces! Sutton and Sutton Park ; Packing- 
ton Park. 
