spines. The perfect insect rather resembles a full-grown bug, being semi-globose, light brown, with black margin round the elytra. There is a variety which is altogether dark-brown. The larva skin splits, but is not thrown off when the insect assumes the pupa state. When the imago, or perfect insect, issues from its double shell, it is white, turns round (head towards tail of skins), and sits in this position upon its former envelopes for twenty-four hours before it moves off. During this time it gains its proper colouring. It is common at all seasons, but especially from March to September, and in all stages of the metamorphosis, the larva generally fixing itself to the underside of the leaf when its transformation approaches.

3. Lecanium nigrum (black bug).—The male of this species is unknown to me. The female is shield-like, much larger and flatter than the brown bug, colour from yellowish grey to deep brown and almost black, according to age; sub-oval, back with one longitudinal and two concentric oval costa on disc, towards the margin slightly corrugated. The shell, seen through a microscope, is found to be composed of minute compartments, like the pavement of a street. Anal slit, and flab as in female brown bug. Old female shield-like, black, with slight longitudinal costa.

Larva, with two long, black anal setæ and projectile tube. This species occurs alone and intermixed with the brown bug, but it is very distinct and at once recognised. It is much less abundant, and therefore of no importance to the planter. I have not succeeded in raising parasites from it.

In the natural course of my observations, I must now mention a fungus, viz. :—

4. Syncladium Neitneri, Triposporium Gardneri.—As soon as the bug has fairly established itself upon a coffee-tree, this latter begins to be covered with a fine black tissue, which upon examination proves to be a fungus of the above name. It comes and goes after the bug-never alone; first it has the appearance of a thin, diluted blackwash, but, rapidly increasing in density, within two or three months it quite covers and blackens the leaves and other parts of the tree, finally almost resembling moss. Its period of growth seems to extend over

about twelve months, when it is replaced by a young growth, or leaves the tree with the bug. When leaving the tree it peels off in large flakes. As the occupation of a coffee or any other tree gives rise to the appearance of a glutinous, saccharine substance-honey-dew (either a secretion of the bug or the extravasated sap which flows from the wounded tree, but more probably a combination of both)—which disappears with the bug, and as the fungus does exactly the same, I have no doubt that its vegetation depends upon the honey-dew. There appears to be some doubt whether there are one or two species of this fungus upon the coffee-tree. The late Dr Gardener sent a specimen to the Rev. Mr Berkeley, the eminent English cryptogamist, who described it as T. Gardneri. I sent two years ago, specimens both to Mr Berkeley and Dr Rabenhorst of Dresden, when the latter named it S. Neitneri, informing me, upon inquiry, that it was quite different from the Triposporium, having simple sporæ, whilst those of the latter are composite. Mr Berkeley said that he was not certain whether the specimen I sent him was in a different state or a different genus from his Triposporium. Remembering the extraordinary changes plants of such simple organism as the one under consideration undergo in the course of their development, I should feel inclined to think that Syncladium and Triposporium are one and the same, but am unable to finally decide on this point, which, moreover, is of little consequence. Of more interest is it that Dr Rabenhorst received the identical fungus, at the same time, from me and from a correspondent in Nizza (Nice), where it covers the leaves of the olive-tree in the same manner as it does the coffee-tree here. It would be curious to know whether its development there depends upon honey-dew, as, to all appearances, it does here.

I now add some general observations on the coffee-bug.

Most planters with whom I have conversed on the subject, not being entomologists, appeared to look upon the coffee-bug as something most unaccountable, almost mysterious, entertaining very erroneous and extraordinary ideas regarding it. The fact is that there is nothing whatever unusual or extraordinary about it, excepting the apparent capriciousness with NEW SERIES.-VOL. XV. NO. I.-JAN. 1862.

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which it comes and goes: now rapidly spreading over a whole estate, now confining itself to a single tree amongst thousands; here leaving an estate in the course of a twelvemonth, there remaining for ever; and so forth. The members of this family of insects (Coccida), to say nothing of the entire order (Homoptera), are in many instances of very great economical importance. I have already mentioned the cochineal and lac insects as amongst the most prominent in this respect; but whilst these are useful, there are, on the other hand, others which are an excessive nuisance to the gardener and agriculturist. Foremost amongst these ranks, undoubtedly, the coffee-bug; and the blight of the sugar-cane in the Mauritius also belongs to this family (Aspidiotus ?). In an entomological point of view, these insects are interesting from other The habits of the Coccidæ have, consequently, long since been the object of study with entomologists. Westwood (Introd, 1840) in his bibliographical reference of the Coccidæ, mentions not less than between thirty and forty authors who have written on this subject. In fact, every general entomologist, from Linnæus downwards, has noticed them. The study was facilitated by the circumstance that there are many species indigenous to Europe.

reasons.

Although, as above stated, the coffee-tree has been known in Ceylon for about two hundred years, and although systematically worked estates have existed since 1825, the bug does not appear to have attracted attention, that is to say, not to have appeared in large quantities, till about 1845, when, however, it began to spread with such rapidity that, in 1847, a very general alarm was taken by the planters. It will be remembered that about the same time the potato, vine, and olive disease began to become very alarming in Europe. With reference to this comparatively recent appearance of the bug in the island, it has been suggested, that it was not indigenous, but had been introduced with seed coffee from some other country. However, the grounds for this assertion are insufficient, and I consider it as indigenous, seeing that it is found upon many other plants besides coffee: I have seen the white bug upon orange, guava, and other trees, also upon vegetables, beet-roots, &c. The brown bug is still less particular, and

attacks almost every plant and tree that grows on a coffee estate, more particularly, though, such as are grown in gardens: guavas, hibiscus, ixoras, justicias, oranges-everything, even weeds. It has also been said that the brown bug came originally from the wild guava (Psidium pyriferum) upon the coffee; but this seems to me improbable, because I have never seen the guava bugged in its wild state, and I have had very good opportunity for observation. It is, however, not to be denied that the bug gives it a decided preference, when it grows with other trees on a coffee estate. I have already alluded to the capriciousness of the bug: why, as is its wont, instead of spreading itself evenly over an estate, as one would expect it to do, it should attack a certain field only, then after a while leave that and go to another, and then to another, and another, it would not be easy to explain satisfactorily. All that is certain is, as I have already mentioned, that the white bug prefers dry, and the brown bug damp localities; and this is to be observed more in detail on any individual estate. The brown bug will be found more plentiful in close ravines, and amongst heavy rotting timber, than on open hillsides. The shifting from place to place depends, probably, upon this predilection of the insect. The bug, of course, seeks out the softest and most sheltered parts of the tree: the young shoots, the underside of the leaves, and the clusters of berries. injury done by the white species seems worse than that of the brown, but not being so plentiful as the latter, it is of less general importance. The white bug is especially fond of congregating amongst the clusters of berries, which drop off from the injury they receive: trees often lose their entire crop in this manner. The injury of the brown bug seems to have a more general effect, by simply weakening the tree; but the crop does not drop off altogether, nor so suddenly. With white bug on the estate the crop can hardly be estimated; with brown bug it can.

The

With regard to the nature of the injury a tree receives from the bug, it may be said that a tree thus attacked suffers from loss of blood (sap), and from partial starvation and suffocation. In this manner, the bug, by means of its sucker, deprives the tree of its sap, that is its blood and nourishment, after it has entered

the organism; whilst the fungus, which never fails to attend upon the bug, with its rootlets and otherwise, closes a vast number of the stomates through which the tree breathes and perspires, thus impeding its respiration. It is, moreover, probable that a tree covered with fungus, being, as it were, placed in the shade, the due decomposition of the carbonic acid of the atmosphere is prevented in such cases, and that the rootlets of the fungus act in a manner very similar to the sucker of the bug. It is not to be wondered, then, that a tree covered all over with bug and fungus should get exhausted. Bug exists on the estates to an incalculable extent; none, I believe. are quite free from it. A thoroughly bugged tree will hardly produce any crop at all. Whole estates are seen "black with bug," that is, with the fungus. Am I wrong in saying that if there was no bug in Ceylon it would, at a rough guess, produce 50,000 cwts. more coffee than it actually does? The value of this quantity on the spot being about L.125,000, this sum would represent the aggregate of the annual loss by bug sustained by the planters. But this is not all: the value of an estate on which bug appears to be chronic is, of course, much less, yielding less crop than that of a clean one.

I have been asked how the bug came to an estate? The eggs, which are a mere dust, are carried about by birds or insects to whom they adhere, or by the wind. If these are deposited in a favourable place they will hatch, and we have then the bug in the larva state. The larvæ in course of time assume a more perfect form, the pupa state, and eventually change into the imago or perfect insect. In the larva state the male and female brown bug are not distinguishable; but in the pupa state the male is very distinct, having all the characteristics of the perfect insect about it. In the white bug the male and female larvæ and pupæ are always distinct. The perfect males either do not feed at all, or if they do, it is probably upon honey-dew, for having no sucker they cannot feed like the females. The number of eggs produced by a female brown bug is about 700. Those of the white bug are not so numerous. The species of bugs indigenous to cold climates produce but one generation of young annually; the propagation in our species being continuous, accounts, in a great measure,