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Show 820 DR. A. G. BUTLER ON LEPIDOPTERA [NOV. 17* camped at Bandawe about the last clay of October, 1885. Bandawe, I might here mention, is a terrible spot for thunderstorms. " In Henga, the valley of the Upper Lunyina Biver, 3300 feet alt., on the mean, some fifty miles S.W. of Deep Bay, tbe early rains fall about the beginning of November and the rainy season ends about the beginning of May, though there may be, aud very often are, a good few showers after that. " O n the Konde plains, which commence about thirty miles north of Deep Bay and extend to the lofty Wakinga Mountains in German territory, the rains are a week or two later than at Deep Bay. At Karonga, the terminus of the so-called Nyasa- Tanganyika "road" (no road in reality exists-it is only a native track), the first rains do not fall before the beginning of December, as a rule. The dry season there commences at the beginning of May, or possibly a little earlier, according to the phase of the moon. "The Nyasa-Tanganvika plateau:-rains commence in November, about the beginning of the mouth on the escarpments of the plateau, and about a fortnight later halfway across, and last until the end of April. The rainfall is very heavy, especially at the extremities of the plateau: nevertheless, towards the end of the dry season, much of it is a desert almost, for want of water. " In the Loangwa Biver valley, Senga, some seven or eight days' journeying on foot S.W. of Karonga, the preliminary rains commence in September ; and, I believe, the rainy season lasts till May, though I was not there to see this for myself. In August, 1895, I found the Loangwa valley completely burnt up ; on September 10th we had rain, also on one or two days subsequently. " In the Eastern watershed of the Congo, I. e. on Lake Mweru, and in Kabwiri and Itawa, the preliminary rains fall in September, and the rainy season lasts on into May. During m y period of residence on Lake Mweru, I found the rainy season of 1891-1892 ended M a y 6th on the level of the Lake; a fortnight later on the plateau to the eastward: the preliminary rains of 1892-1893 again began on September 4th, some three weeks earlier than was the case in 1891." All Mr. Crawshay's captures having been carefully dated, it will now be possible for any Lepidopterists, by going through my published papers, to discover whether a form was obtained in the dry or wet season ; in any case it is certain that some of the supposed distinctly seasonal forms were all captured at the same spot on the same day, and (to judge by their excellent condition) must have emerged from the pupa about the same time; but I am told that this fact does not militate against the view that they are dry- and wet-season forms! Personally, I fail to understand how* an insect which flies abundantly in the middle of the rainy season can be called a " dry-season form "; I can only suppose that the expression " dry season" is not to be understood literally, but merely as indicating a type of form and colouring prevalent during the dry season, though often occurring during the rains. |
