weak limbs, and the beetle is more than twice its size and weight, and is very active, quickly taking wing; so that the only way in which it could have been overcome that I can think of, is by the bug creeping up when it was sleeping, quietly introducing the point of its sharp proboscis between the rings of its body and injecting some stupifying poison. In both instances that I witnessed, the bug was on a leaf up a shrub, with the bulky beetle hanging over suspended on its proboscis. Other species of bugs certainly inject poisonous fluids. One black and red species in the forest, if taken in the hand, would thrust its sharp proboscis into the skin, and produce a pain worse than the sting of a wasp. Amongst the bushes were always to be found the beautiful scarlet and black tanager (Rhamphocœlus passerinii, Bp.), and more rarely another species (R. sanguinolentus, Less.). Along with these, a brownish-coloured bird, reddish on the breast and top of the head (Phænicothraupis fusicauda, Cab.), flew in small sociable flocks; whilst generally somewhere in the vicinity, as evening drew on, a brown hawk might be seen up some of the low trees, watching the thoughtless chirping birds, and ready to pounce down when opportunity offered. Higher up the valley more trees were left standing, and amongst these small flocks of other birds might often be found, one green with red head (Calliste laviniæ, Cass.); another, shining green, with black head (Chlorophanes guatemalensis); and a third, beautiful black, blue, and yellow, with yellow head (Calliste larvata, Du Bus.). These and many others were certain to be found where the climbing Marcgravia nepenthoides expanded its curious flowers. The flowers of this lofty climber are disposed in a circle,

Ch. VIII.] FLOWERS FERTILIZED BY BIRDS.

129

hanging downwards, like an inverted candelabrum. From the centre of the circle of flowers is suspended a number of pitcher-like vessels, which, when the flowers expand, in February and March, are filled with a sweetish liquid. This liquid attracts insects, and the insects numerous

insectivorous birds, including the species I have mentioned and many kinds of humming-birds. The flowers are so disposed, with the stamens hanging downwards, that the birds, to get at the pitchers, must brush against them, and thus convey the pollen from one plant to another. A second species of Marcgravia that I found in the woods around Santo Domingo has the pitchers placed close to the pedicels of the flowers, so that the birds must approach them from above; and in this species the flowers are turned upwards, and the pollen is brushed off by the breasts of the birds. In temperate

K

latitudes we find many flowers fertilised by insects attracted by honey-bearing nectaries; and in tropical America not only bees, moths, and other large insects carry the pollen from one flower to another, but many flowers, like the Marcgravia, are specially adapted to secure the aid of small birds, particularly humming-birds, for this purpose. Amongst these, the "palosabre," a species of Erythrina, a small tree, bearing red flowers,

FLOWER OF PALOSABRE.

that grew in this valley, near the brook, often drew my attention. The tree blooms in February, and is at the time leafless, so that the large red flowers are seen from a great distance. Each flower consists of a single long, rather fleshy petal, doubled over, flattened, and closed, excepting a small opening on one edge, where the stamens protrude. Only minute insects can find access to the flower, which secretes at the base a honey-like fluid. Two long-billed humming-birds frequent it; one (Heliomaster pallidiceps, Gould), which I have already mentioned, is rather rare; the other (Phaethornis longirostris, De Latt.) might be seen at any time when the tree was in bloom, by watching near it for a few minutes. It is mottled brown above, pale below, and the two middle tail feathers are much longer than the others. The bill is very long and curved, enabling the bird easily to probe the long flower, and with its extensile cleft tongue pick up the minute insects from the bottom of

Ch. VIII.]

FOXGLOVE AND HUMBLE-BEE.

131

the tube, where they are caught as if in a trap, their only way of exit being closed by the bill of the bird. Whilst the bird is probing the flower, the pollen of the stamens is rubbed in to the lower part of its head, and thus carried from one flower to fecundate another. The bottom of the flower is covered externally with a thick, fleshy calyx-an effectual guard against the attempts of bees or wasps to break through to get at the honey. Humming-birds feed on minute insects, and the honey would only be wasted if larger ones could gain access to it, but in the flower of the palosabre this contingency is simply and completely guarded against.

Many flowers have contrivances for preventing useless insects from obtaining access to the nectaries. Amongst our English flowers there are scores of interesting examples, and I shall describe the fertilisation of one, the common foxglove, on account of the exceeding simplicity with which this object is effected, and to draw the attention of all lovers of nature to this other branch of a subject on which the labours of Darwin and other naturalists have of late years thrown a flood of light. The pollen of the foxglove (Digitalis purpurea) is carried from one flower to another by the humble bee, who, far more than the hive bee, that "improves each shining hour," deserves to be considered the type of steady, persevering industry. It improves not only the hours of sunshine, but those of cloud, and even rain; and, long before the honey-bee has ventured from its door, is at work bustling from flower to flower, its steady hum changing to an important squeak as it rifles the blossoms of their sweets. The racemes of purple bells held up by the foxglove are methodically visited by it, commencing at the bottom

flower, and ascending step by step to the hig four stamens and the pistil of the foxglove closely against the upper side of the flower stamen on one side opens its anthers and pollen. The humble-bee, as it bustles in, b off. Then another stamen exposes its polle other side, then another and another; but not pollen has been brushed off does the cleftpistil open, and expose its viscid stigma. Th bee brushes off the pollen into its hairy coa upper flowers of one raceme and carries it d lowest flowers of another, where the viscid s open and ready to receive it. If the humbl first to the upper flowers of the spike and downwards, the whole economy of this plant cross fertilisation would be upset.* The oper the foxglove hangs downwards. The lower dilated opening of the tube, is turned outward: scattered stiff hairs distributed over its inner above these the inside of the flower hangs almos dicularly, and is smooth and pearly. The large bee bustles in with the greatest ease, and uses the as footholds whilst he is sucking the honey; but the bees are impeded by them, and when, having at las gled through them, they reach the pearly, slippery pi above, they are completely baffled. I passed the a

Darwin mentions having secu humble bees visiting the i ing spikes of the Spiranthis autumnalis (ladies' tresses), and n that they always commenced with the bottom flowers, and crav spirally up sucked one flower after the other, and shows how proceeding ensures the cross fertilisation of different plants.—“ tilisation of Orchids," 127.