100 A NIGHT WITH A MICROSCOPE. 
of the fly was the foot, the pad of which secreted the glutinous 
substance which they had observed after the insect had walked 
across polished glass. After dealing with the breathing tubes 
of insects, such as the spiral filament inside a caterpillar, Mr 
Ovens spoke on the wing of a butterfly, pointing out that the 
powdery substance which adhered to the hand that touched it 
was composed of beautiful scales, each so infinitesimal that on 
every square inch of wing surface the number of scales was 
reckoned at 100,000. The antannz or horns of insects presented 
another series of organs of endless variety, and of all conceivable 
forms. In the case of ants, observation showed that by means 
of their antenne communication and recognition were estab- 
lished. The lecturer likened the sting of a hornet unto a fishing 
hook or arrow head, but a curious point was that the possession 
of stings was only enjoyed by the female. |The Ovipositers 
were all highly interesting objects, but perhaps none more so 
than those of the saw fly, where a pair of elaborate toothed saws 
slid backwards and forwards with great rapidity. The Ticks 
were characterised as wingless, degenerated parasites, which 
lived on all sorts of creatures, a good example of the species 
being the sheep tick, which lived on the sheep solely by suction. 
The far-off date of 1670 saw the advent of the Simex lectularius 
or what was commonly known as the bed bug. It had been 
said that this troublesome and repulsive insect was imported in 
the timber brought from America for use in rebuilding the city 
of London after the great fire. At first its bites were mistaken 
for plague spots; but in the middle of last century the insect 
got the title of bug or goblin. Aphides or Plant Lice were next 
spoken of. By a surprising departure from the common law 
of nature, each female of the species of insects could alone pro- 
duce many generations of offspring. Another peculiarity 
about the family was the fact that females were exclusively pro- 
duced in the spring, no males being found until the autumn. 
Referring to the difficulty of defining the difference between 
animal and vegetable life, he said, for instance, the Volvox 
globator was a wonderfully endowed plant which moved about 
in a wonderful manner, and in that small part of the creation 
the 50th part of an inch. This plant was to be found near 
Dumfries, in Babington Loch, Maxwelltown, though not in 
great quantity. Ditoms were also dealt with. 
