All seasons of the year (except when too great an abundance of a favourite flower abounds) yield a certain percentage of moths attracted by sugar. Mild nights in the depth of winter, or in very early spring, sometimes afford rarities, and certainly many hybernated common species. Warm, cloudy nights, with a little wind stirring, are generally the most favourable; but one of the best nights I ever had amongst the "Peach Blossoms" and "Buff Arches" (Thyatira batis and derasa) was in a wood in Warwickshire, when the rain fell in torrents, accompanied with fierce lightning and thunder, from about 11 p.m. until 6 the next morning. On this night everything swarmed, a hundred or more common things on one patch of sugar being of frequent occurrence.
Moonlight nights are, as a rule, blank ones for the "sugarer" — (Do the moths fly high to the light?) — but I once had a grand capture of many specimens of the "sword-grass" (C. exoleta) on a bright moonlight and very windy night in February; and Dr. Knaggs says that on one occasion he met with night-flying moths literally swarming on a sugared fence in a field once in his possession, whither, in the small hours, he had taken a stroll with a friend on the brightest moonlight morning it was ever his lot to behold.
Many nights which appear the most favourable will, on the contrary, be unaccountably disappointing; not a single moth will make its appearance. The presence of ground-fog, "honeydew," more attractive flowers, or a coming change of wind or temperature (nothing caring to stir in an east, north, or northeast wind) will sometimes account for this.
"Showers, rain, thunderstorms, provided they are accompanied by warmth, are," says Dr. Knaggs, "very favourable, and the catch during these conditions of the atmosphere will generally repay the inconvenience of a wet jacket. On one terrible night, when the lightning was perfectly terrific, almost blinding even, though my companion's eyes and mine were kept upon our work, an incredible profusion of moths of various kinds were hustling one another for a seat at the festive board, and continued thus to employ themselves until a deluge of rain swept both sweets and moths away from their positions. On another stormy night, I well remember having counted no less than a hundred and fifty moths of several sorts and sizes struggling for the possession of two small patches of sugar. Perhaps the best condition of the air may be described as cloudy overhead, but clear and free from ground-fog near the earth; and when this state of things has been preceded by sultry weather, and a steady west, south, or south-west wind is blowing at the time, the collector need not fear the result, for he can hardly fail to be successful."
July is usually one of the very best months for sugaring, and, if warm, what can be more charming than to select a fine night at this season of the year and to spend it in the woods?
Just before dusk get your sugar painted on the trees, at about the height of your chest, in long narrow strips, taking care not to let any fall at the foot of the tree or amongst the adjacent bushes (though I have sometimes done very well by sugaring low down near the foot of the tree). Just as the nightjars and bats begin to fly you will have finished the last tree of your round, and rapidly retracing your steps to the first you will perhaps see a small moth, with wings raised, rapidly flitting up and down your patch of sugar. This is most probably the "Buff Arches," usually first to come; in fact, during the summer months, it is perhaps as well to get the sugar on at eight o'clock, as I have known this species, the "Peach Blossom" and the "Crimson Underwings" (Catocala promissa and sponsa), to come on the sugar in bright light while yet the last rays of the sun were lighting the westward side of the tree-trunk, when all the rest lay in shadow.
Fig. 52 — Impaler.
If you are not facile princeps at "bottling," do not attempt it with the three or four species named above, but strike them with the net at once, for they are the most skittish of noctuae, especially in the early part of the evening. Striking down such insects with a parchment-covered battledore, which Dr. Guard Knaggs considers inflicts the least injury, or impaling them with a triangle of needles stuck in cork, in the manner shown in Fig. 52, or even with a single darning needle, has been recommended, but after a trial I have come to the conclusion that such plans are clumsy in the extreme.
A little practice will enable the beginner to dispense even with the net, which tends to "rub" such dashing or unquiet insects, and to rapidly cover them with a large cyanide bottle, or, failing this, with the instrument shown in Fig. 53, which is a combination of the "drum" and cyanide bottle, and will be found very useful for skittish insects. A, represents a cyanide bottle with no neck — a wine or ginger-beer bottle cut down, by filing it around, and then tapping it smartly, does very well on an emergency.