130 THE MICROSCOPICAL NEWS. 
doubted. Its flexibility is such as to give it a greater range than 
any of the other organs, allowing it either to operate on a small 
point or to flatten itself out upon a comparatively large surface. 
It is not unlikely that the labium is used, as it is by the male, for 
gathering up the secretions of flowers, but a possible explanation of 
its use along with the other organs has occurred to me which is. 
perhaps worth mentioning. The bite of the Gad-fly is so acutely 
painful that the attention of any animal attacked by it is at once 
drawn to the punctured spot, and in the majority of cases the insect 
must be almost immediately dislodged. When it returns to the 
attack, as it soon does, it finds an accumulation of fluid which has. 
exuded from the wound ready for imbibition by the labium, and it 
is most probable that the delicate titillating movement of the organ, 
far from causing any further uneasiness, will tend actually to allay 
the irritation before set up. An undisturbed and plentiful meal 
can then be enjoyed, for so long as the blood is prevented from 
coagulating it will continue to flow from the puncture. Should, 
however, the insect have been allowed to pursue its operations from 
their commencement without molestation, the labium, in addition 
to performing this probable function of soothing titillation, will aid 
the sete by appropriating any fluid which may escape them at the 
edges of the wound. 
Last summer I had an opportunity of watching a Gad-fly at work 
on the back of my hand. I did not attempt to use a pocket lens 
for fear of disturbing it, but I was nevertheless able to obtain a 
tolerably good view of its operations. On alighting, it appeared to 
search about, as well as I could make out, with the labium principally, 
until a favourable spot was found, then a steadying movement of 
the whole body took place, down went the head and a sharp pain 
informed me that the sete were doing their duty well. At the 
same time the labium could be felt, as well as seen, playing freely 
around the spot. This went on for some time, perhaps a minute, 
until an unguarded movement frightened my guest away, and 
abruptly terminated an interesting observation. <A slight quantity 
of blood exuded afterwards from the puncture. The insect, how- 
ever, did wo¢ return to make use of this, and I was therefore unable 
to verify my hypothesis. Man is, of course, a very occasional 
victim, but cattle and horses suffer severely in localities where the 
Gad-fly abounds. The species whose oral organs have been 
specially under consideration is amongst the least formidable. 
Several species of the genus Tabanus possess setze of nearly twice 
the length, and the armature of the mandibles and maxillz is 
proportionately developed. It is not surprising, then, that cattle 
should exhibit so much restlessness when in the vicinity of these 
winged foes, armed as they are with instruments against which even 
a thick skin forms a very insufficient protection. 
