482 MOTIONS OF INSECTS. 
they appeared a concatenated series of insects (as Reaumur has here de- 
scribed his Ephemere) moving in a spiral direction upwards ; — but each 
series, upon close examination, we found was produced by the astonish- 
ingly rapid movement of a single fly. Indeed, when we consider the space 
that a fly will pass through in a second, it is not wonderful that the eye 
should be unable to trace its gradual progress, or that it should appear 
present in the whole space at the same instant. The fly we saw was a 
small male Ichneumon. 
Other circular motions of sportive insects take place in the waters, 
Linné, in his Lapland tour, noticed a black Tipula which ran over the 
water, and turned round like a whirlwig, or Gyrinus.! This last insect I 
have often mentioned ; — it seems the merriest and most agile of all the 
inhabitants of the waves. Wonderful is the velocity with which they turn 
round and round, as it were pursuing each other in incessant circles, 
sometimes moving in ‘oblique, and indeed in every other direction. Now 
and then they repose on the surface, as if fatigued with their dances, and 
desirous of enjoying the full effect of the sun-beam : if you approach they 
are instantaneously in motion again. Attempt to entrap them with your 
net, and they’are under the water and dispersed in a moment. When the 
danger ceases they reappear, and resume their vagaries. Covered with 
lucidatmour, when the sun shines they look like little dancing masses of 
silver or brilliant pearls.? 
But'the motions of this kind to which I particularly wish to call your 
attention ‘aré*the choral dances of males in the air ; bor the dancing sex 
amongst! insects \is the masculine, the ladies generally an themselves 
quiet at home.’ These dances occur at all seasons of the year, both in 
winter and summer, though in the former season they are confined to the 
hardy Tipulariz. In the morning before twelve, the Hoplie, root-beetles 
before mentioned, have their dances in the air, and the solstitial and com- 
mon cockchafer appear in the evening—the former generally coming 
forth at the summer solstice — and fill the air over the trees and hedges 
with their myriads and their hum, Other dancing insects resemble moving 
columns — each individual rising and falling in a vertical line a certain 
space, and which will follow the passing traveller — often intent upon 
other business, and all unconscious of his aérial companions — for a con- 
siderable distance. ° 
Towards ‘sunset the common Ephemere (Z. vulgata), distinguished by - 
their spotted wings and three long tails (eaudule), commence their dances 
in the-méadows near the rivers. They assemble in troops, consisting some- 
times’ of several hundreds, and keep rising and falling continually, usually 
over some high tree. They rise beating the air rapidly with their wings, 
till they have ascended five or six feet aboye the tree ; when they descend 
to it with their wings extended and motionless, sailing like hawks, and 
having their three tails elevated, and the lateral ones so separated as to 
form nearly a right angle with the central one. These tails seem given 
1 Lach, Lapp. i, 194. 
2 Compare Oliv. Zntomol. iii. Gyrinus 4. One species, howeyer, Gyrinus (Orech- 
tocheilus) villosus, which, as before observed, pursues its dances only at night, differs 
also from its congeners in not haying the same habit of diving, or at least not in the 
daytime, when if forced into the water from its hiding-places under stones, all 
its efforts are confined to endeavouring to regain the shore, (Ann, Soc. Lint. de 
France, iy. bull, 1xxx.) t 
