Disturbing insects, and thus causing them to start forth, and so render themselves visible, is another method of collecting. This is carried out in various ways.
First, the occupants of high trees may be expelled by jarring the trunk with a heavily loaded mallet, or by thwacking the trunk with a long hazel stick; but a sharp look-out must be kept, for some sham death, and fall plump down, while others make off as fast as they can. Other plans are to pelt the trees with stones, or pump on them with a powerful garden engine, or beat them with a long pole; and of all tress the most profitable for this purpose is the yew; though firs, oaks, beeches, and other trees are not to be despised.
Fig. 13. Frame of Cage for Virgin Lepidoptera.
For beating bushes there is nothing better than a walking-stick, and for low herbage a long switch passed quickly from side to side with a tapping movement is best adapted. The tenants of tree trunks may be disturbed by brushing the surface with a leafy little bough, or, better still, by the use of a strong fan, with which a powerful blast may be driven, the net being held in such a position as to intercept such insects as are blown off.
Thatch-beating in the autumn is a very profitable employment, particularly in the matter of Depressariæ. Sweeping need only be mentioned here, for moths collected by the process are anything but perfect insects.
There are various methods of attracting moths and butterflies. The first is effected by confining a virgin female in a muslin cage, the frame of which may be very readily formed by bending three pieces of cane into circles, and fixing these together at right angles, as shown in [Fig. 13]. When this baited cage is placed in a favourable position, and the weather is propitious for the flight of the males, the latter will, in some cases, congregate, and may be freely captured.
Then, the food-plant of the species is an attraction at which we stand the best chance of procuring impregnated females.