A rare variety, very much like the commoner type just described, is occasionally seen in Kent and Surrey. It is called the Late Spider Orchis (variety _arachnites_), and is supposed to resemble a spider more than a bee. The petals are more triangular than in the Bee Orchis, and the lip is longer than the sepals. It may also be distinguished by the appendage in the notch, which is cordate in form, and flat. Another rare plant--the Spider Orchis (_Ophrys aranifera_) is to be found in chalky pastures of the South-East. Its flowers are smaller, and generally fewer in number. The sepals are yellowish-green inside, and the petals smooth and linear. The lip is swollen and four-lobed, but without any appendage in the notch, and is of a deep purple-brown, with yellowish markings. This is an earlier species, flowering during April and May. Our last example of this order is the pretty little Fly Orchis (_Ophrys muscifera_). It is a slender plant, with a few oblong leaves, and usually from two to ten flowers arranged in a loose spike. The sepals are yellowish-green, and the very slender petals resemble the antennæ of an insect. The lip of the flower is of a brownish purple colour, with a blue blotch in the middle; and is oblong, with three lobes, the middle of which is divided into two. This species grows from six inches to a foot in height, and flowers from May to July. It is moderately common in the open spaces and on the banks of some calcareous districts. Although a great variety of Grasses (order _Gramineæ_) are to be found on calcareous soils, there are two common species which are almost exclusively confined to dry, chalky pastures. One is the Downy Oat Grass (_Avena pubescens_), which flowers in June and July. It has a creeping stem, and grows from one to two feet high. The radical leaves are short, hairy, with sharply-pointed ligules, and terminate abruptly in a sharp point. The flowers are arranged in a nearly simple panicle, with erect spikelets of five or six flowers. The glumes are nearly equal, the inner one with three ribs. The flowering glume is divided at the tip, and provided with a long, bent, twisted bristle. The other, numbered 7 on Plate VIII, is the Yellow Oat Grass (_A. flavescens_), which grows to about the same height, and flowers at the same time. In this species the radical leaves are hairy, and also terminate suddenly in a sharp point. The panicle is much branched, with erect spikelets of five or six flowers. In this one, too, the inner glumes have three ribs, but it may be distinguished from the last by the two terminal bristles of the inner scales, and by the blunt ligules (appendages at the base) of the sheathing leaves. XIX BY THE RIVER SIDE