'January 9th.-I and a Maori have just dug up a vegetable caterpillar from under the roots of a 'rata.' There are lots of them just here; he is digging for a third. He says they go under ground in February, and it takes years for the vine (or tendril fungus) to grow to its full length. The tendril appears about four or five inches above the ground generally, but often much more. The whole length of the largest tendril I saw to-day was about nine or ten inches. Some of the caterpillars appeared much fresher than others. The end of the tendril is like the velvety-looking part which grows from the centre of an Arum flower, or the end of a reed (Typha ?), and tapers off. The caterpillar itself lies close under the root of the 'rata'; the soil where we found them to-day was the ordinary good bush soil. I afterwards went with the native to see what he said was the living caterpillar before it buried itself: there seemed plenty of them in the Kumari's leaves at Pokinhoe. They were green and black, with a horn at the tail, from which he said the tendril grew. Went in the afternoon and dug up half a dozen. There seemed to be any number growing about where we found the first this morning. I am sure the longest tendril was quite a foot long."

The supposition of the growth requiring years, and the repetition of the connection between the buried caterpillars and those of a Sphinx must be discarded. It is, however, only just, in this connection, to quote the remarks of Dieffenbach, who has fallen into the same error in his "Travels in New Zealand." He says it is called "Hotete" by the natives; and in his appendix, under the name of Sphinx, states: "The caterpillars feed on Convolvulus Batatas. The Sphæria Robertsii is found parasitical on this caterpillar, which only occurs at the roots of the 'rata' (Metrosideros robusta).”

Let us refer to the account given by Dr. Hooker of this same production, in a letter quoted in the Journal of Botany, p. 209 (1841) :

"About Sphæria Robertsii 1 collected all the information, and as many specimens as I could, but am still much at a loss to account for its development. They are found in spring, generally under tree-ferns; the caterpillar is buried in the ground, as is the lower portion of the fungus. Now both these fungi (that is, the present and Torrubia Taylori, another Australasian species) belong to caterpillars which bury themselves for the purpose of undergoing the metamorphosis; and both Mr. Taylor and Mr. Colenso hold the same opinion, that in the act of working the soil, the spores of the fungus are lodged in the first joint of the neck, and the caterpillar settles head upwards to undergo its change, when the vegetable develops itself. I do not remember you have remarked in your 'Icones' that the entire body of the insect is filled with a pith, or corky vegetable substance, and that the intestines are displaced, which my specimens in

spirits show well, and then what does the muscular fibre of the animal become? It must, I suppose, be all turned into vegetable, for the skin of the creatures remains quite sound all the time. This change may take place from the displacement of one gas and development of another; it also occurs in the dark, and is hence somewhat analogous to the formation of fungi on the timber-work in mines. However this may be, the whole insect seems entirely metamorphosed into vegetable, with the exception of the skin and intestines."

A note appended to this extract states that Mr. Dieffenbach determined the moth to which the larva belongs to be Hepialus virescens, whereas we have shown that this gentleman regarded it as a Sphinx. From another source we gather, on the authority of Dr. Jonathan Pereira, additional information on this point:

"Dieffenbach suggests that the insect is a species of Sphinx which feeds on the 'sweet potato;' but the absence of any spine or horn on the last segment of the larva is an objection to this suggestion. Mr. Doubleday thinks that it may be Hepialus virescens, which is found at the root of the rata tree. He has a caterpillar apparently identical with that on which the fungus grows, and which is believed to be the larva of Hepialus virescens." *

There is one discrepancy in Dr. Hooker's account which we cannot at present understand in so excellent a botanist, inasmuch as he declares that the infected caterpillars are found under tree-ferns, whereas in all other accounts the "rata" is named, and this is further strengthened by a passage in the "Report of the Royal Society of Tasmania for 1851," p. 289:

"Major Last states that it is chiefly, if not exclusively, under and above the roots of the 'rata' (Metrosideros robusta) that the plant caterpillar, Sphæria Robertsii, is met with."

In the first instance we were doubtful whether our correspondent had not found another species of vegetable caterpillar, but this doubt was soon dispelled on receiving from him a veritable specimen of Torrubia Robertsii (often called Sphæria Robertsii),† together with the sketches of caterpillar and pupa, from whence our figures are derived.

The other New Zealand species of parasite occurs on the pupa of a cicada, and is the Cordyceps Sinclarii of Berkeley, and the Torrubia cæspitosa of Tulasne.

C.

* Pharmaceutical Journal, vol. ii. p. 592 (1542-3). We may observe that this curious production is figured and described in Hooker's "Icones Plantarum," vol. i. pl. 11; in the "Transactions of the Entomological Society of London," vol. iii. pl. 4; in Lindley's "Vegetable Kingdom," fig. 25; in the "Pharmaceutical Journal," vol. ii. p. 593, fig. 3; in Hooker's "Journal of Botany," vol. iii. pl. 1, fig. A; and under the name of Sphæria Hugelii in Corda's "Icones Fungorum," vol. iv. pl. ix. fig. 129.

SPIDER-CRABS AND THEIR PARASITES. THAT excellent naturalist Mr. Edward Jesse, in

THAT

a short article entitled "The Spider-Crab," in Once a Week" (July 9th, 1859), says :-"There is a very small species of crab at Bognor, the spidercrab, which has its body and claws covered with numerous minute hooks, scarcely perceptible to the naked eye, but perfectly so with the aid of a magnifying-glass. It may be asked 'What are these hooks? You shall hear. This crab is a prodigious coxcomb, and very careful of its own precious person. Either for the purpose of concealing itself from its enemies, or from an innate love of finery, it selects a quantity of seaweed, always preferring the most gaudy colours, those chiefly red. Having selected them, he cuts them into fine thread-like strips, and runs them through the hooks. When he has completed his toilette, he appears one mass of seaweed, thus not only disguising himself from those enemies which might otherwise make him their prey, but perhaps feeling himself the best-dressed crab in the neighbourhood. It is also remarkable that this labour for making his toilette is renewed every morning, so that the quantity of seaweed consumed is very great. This may be observed by any-one who has the opportunity of keeping these comical little crabs in an aquarium, although I regret to add that they do not live long in a state of confinement." Mr. Jesse says that he

wrote this from his own observation, though the discovery of the crab's habits was made by some friends of his. The paragraph I have quoted "went the round of the papers" at the time, and I, who then kept an aquarium shop in London, was soon favoured with many orders for "the Vanity Crab," "the Dandy Crab," "the Crab that togs himself out in seaweed," and so forth. Mr. Jesse adds "they are caught in considerable numbers at Bognor, together with another crab, about the same size as the spider-crab, but which is not furnished with hooks. On speaking to the Bognor fishermen respecting the latter, I found they all entertained the idea that the seaweed grew on them. The thread-like weeds may, however, be drawn out of the hooks one by one, until the little dandy is left perfectly bare."

However, the fishermen were right, and Mr. Jesse and his friends were wrong, for the seaweeds do grow upon the shell of the crab, and are not temporarily attached, as Mr. Jesse describes. It is probable that the Crab referred to is the fourhorned spider-crab (Pisa tetraodon), and Professor Thomas Bell, in his "History of British Stalk-eyed Crustacea" (Svo. 1853, pp. 24, 25), treating of this Crab (which is eminently a Bognor species, by the way), says "it is found concealed under the long hanging fuci which clothe the rocks at some distance from the shore. . . . Like all slow-moving Crustacea, they are liable to be covered with small

fuci,* so that they are sometimes completely covered by a mass of these marine plants growing upon their surface, where their roots find a secure hold amongst the villous coat of the shell and limbs. Say supposes that the fuci which are found covering certain Crustacea, are merely entangled mechanically in the hooked hairs by which they are covered, but there is no doubt that they actually grow upon them and are attached by roots. This is evident from the healthy state of the little plants, as well as from the direction of the branches." Mr. Bell also alludes to various kinds of vegetable and other growths covering other spider-crabs (Stenorhynchus, page 5; Inachus, page 17; Pisa Gibbsii, page 28; and Hyas, pp. 33, 34). My own experiences in these matters coincide with Mr. Bell's. Thus I have often had brought me living specimens of the spinous spider-crab (Maia Squinado), sometimes without any seaweeds on it,

Fig. 165. Four-horned Spider-Crab (Pisa tetraodon). and sometimes quite covered with such algae as Gracilaria, Hypnea, Gelidium, Gymnogongrus, Furcellaria, Polyides, and other seaweeds having thread-like or stiff wire-like fronds; so that when they were washed about horizontally by the sea, their filiform character caused them to become entangled in a complicated manner in the strongly hooked hairs with which Maia is beset, and the weeds could be "drawn out of the hooks as Mr. Jesse describes, but the plants were always attached fast to the crab shell by their roots also. No spidercrab known to me can cut up algæ into strips, nor yet attach such strips to its carapace, at any rate not to its upper portion, for the most they can do

* The word "fuci," as employed in these two instances, is not intended to convey the idea that actual fucaceae are the plants attached to the crabs. Mr. Bell uses it, as did many of the older naturalists, whose general name for nearly all the Rhodosperms was Fucus, in the same manner that they applied the term "Cancer" to almost all crabs, and Actinia to all sea-anemones.

in this way is to use their limbs to "preen" themselves with a little, but always in a very feeble and awkward manner.

Hyas araneus is a spider-crab which I get with a perfectly clean shell when brought up from deep water on a clean sandy bottom, on the coasts of Essex and Kent, and off the island of Heligoland; but when it comes closer in shore and hides among weed-covered ledges of rocks, then these crabs are frequently covered with dense bushes of red algæ (Rhodosperma), and, in explanation of why these plants are red, and not brown (Melanosperma), or green (Chlorosperma)-marine algæ being thus systematically divided into these three great classes by their colour-it has to be stated that the red algæ grow in shady places, and when found between tide-marks, they are generally met with concealed under a curtain of green and brown weeds, which prefer the light. Consequently, as the hiding habits of the crabs cause them to inhabit the same localities as the red weeds, it is natural that the latter should grow on the animals, especially as their rough and hairy shells and slow motion are well adapted for the purpose. But when the red algæ, whether living on a crab or any other object, are found in a place where the shadow is inconsiderable, as, for example, on the seashore, very high up between tide-marks, or in an aquarium, where the light is greater and the temperature higher than in the sea, then the red weed loses its colour, becomes lighter in hue, gets deteriorated, and becomes gradually overgrown with parasitic confervæ. About twelve years ago, Mr. Robert Warington published in the Zoologist an account of some interesting experiments made by him, in which he showed how he restored to their normal condition, some Rhodosperms, which had become overgrown with confervæ, by placing them in variously coloured glass jars, which permitted the growth of one kind of alga, but not the other.

In the Hamburg Aquarium (tank No. 10) are two large spinous spider-crabs (Maia Squinado), which arrived from the coast of France, quite free from any algæ. After they had been here for some weeks their shells began to be rapidly grown over by green algæ, and this had to be removed with much difficulty, by hand. In one corner of the tank is a large and perfectly dark cave, formerly inhabited by a pugnaciously disposed lobster (Homarus vulgaris), who would not allow the spider-crabs to enter its den. But I removed the lobster, and the crabs immediately took possession of the cave, and now, as they pass much of their time in darkness, the algæ have ceased to grow upon them, save to a small extent. The under parts, however, of these slow crabs being ever in almost absolute darkness, have become covered with patches of a compound ascidian, Botryllus polycyclus, a creature fond of shade.

The specimens of Hyas, which I have named as

arriving here in a clean state, from sandy bottoms in deep water, do not long keep clean, however; for remain sluggishly as much as they will in the shadows of overhanging rockwork, their pale buff colour becomes gradually green, which darkens as the carapace gets farther covered with a velvety cout of algae. Some of our Hyas have, in addition, numbers of a small simple (i. e. not compound) ascidian (Cynthia) growing on them, and others have their limbs quite covered with an encrusting Polyzoa. But I have never known any red, or much less any brown algæ spring up on crustacea in aquaria. Nor are active crabs, whether they are occasional burrowers or not, such as, e. g., the common shore crab (Carcinus manas), or the various swimming crabs, as Portunus and Portumnus; nor are essentially burrowing crabs, however slow they may be, for example, Ebalia, Gonoplax, and Corystes, liable to become thus covered with weeds or other parasites, whether in the sea or in captivity, unless in the latter case they are cruelly deprived of sand or other substances to burrow in, and are otherwise hindered from getting into dark places. Some years ago, a lobster (Homarus) was kept in one of the smaller central tanks of the Regent's Park aquarium, where it had no opportunity of hiding, and it became covered with quite a forest of green seaweed (Enteromorpha). Here the same species is similarly grown over, especially in summer, but to a very much smaller extent, as in our aquarium there are many hidingplaces. But our spiny lobsters (Palinurus quadricornis) being of less hiding habits than Homarus, become rather more densely invested with plants in warm weather. These specimens of Palinurus when they first came from the sea, were thickly covered with thousands of a little living tubicolous annelid (Spirorbis communis), the rough carapaces and the prickly peduncles of the great external antennæ of the lobsters forming suitable surfaces for the attachment of the shells of these worms, which have multiplied in the aquarium till they have become quite a nuisance, as they have cemented themselves not only to rough surfaces of the rockwork and slate of the tanks, but also to their glass fronts by hundreds, and have to be scraped off with a steel instrument. One female Palinurus is loaded with eggs, which she carries below the abdomen, with the tail closely doubled under, so as to keep the spawn in a kind of pocket thus formed. In this state she is not so active as her fellows, and she is placed in a separate tank, so as not to be disturbed by them; and as a consequence of her slowness she has become grown over on various parts of the lower surface of her shell with a great family of living branching Polyzoa. Trifling as is the motion of the creature in her present condition, it may be enough to imitate the waving motion of the sea, in a greater degree than is given by the current of

water which usually flows through the tank, while the roughness and darkness of the lower half of the animal's crustaceous covering may supply the other conditions necessary for the well-being of this kind of Polyzoa, so seldom kept in aquaria alive.

Slowly moving Crustaceans, however, are not the only animals on the shells of which live other animals and various forms of vegetation. The periwinkle (Littorina), for example, is often found with fucus (Tang) growing upon it, this plant inhabiting the zone of extreme high water, in which the mollusc also lives. But no mollusc with which I am acquainted is so interesting in this respect as the very slow and very rough rock-winkle (Murex erinaceus), when dredged up in Weymouth Bay, in Dorsetshire. Most of the specimens from this locality have attached to them beautiful little healthy fronds of Rhodymenia, Iridea, Chondrus, Phyllophora, and other red algæ, in fine condition, and well adapted from their small size for aquarium purposes. I often obtain them, hoping that the habits of the Murex will carry the weed into dark corners of the tanks, where the plants will continue to flourish. But after a time they become covered with dirty-looking confervæ, and lose their freshness of appearance, like all other red algæ in captivity and in too much light. The successful aquarium cultivation of Rhodosperms free from confervæ, and under circumstances enabling these plants to be readily seen in the very subdued light they require, is a thing to be yet learnt. But I some

Fig. 166. The Spider-Crab (Hyas araneus).

times by chance manage them very well. Last week (April 28th), for instance, I had occasion to examine the state of our two marine filters, which are a pair of slate tanks, seven feet long, and three feet broad and deep, closely covered over with wooden flaps, so that the insides of the vessels are always in total darkness. They are filled to within about six inches of their tops with fine sand, through which constantly flow strong currents of sea-water. Into these filters I from time to time throw surplus

specimens of red algae of various species, and on looking at these on the day named, I found them all nicely growing, having the delicate, plump, transparent pinky-red colour, which is characteristic of them when in the sea, under the most favourable circumstances, while plants of the same species which at the same time I carefully deposited in the tanks, have become so entirely grown over with confervæ, that their character is lost. In Hardwicke's SCIENCE GOSSIP for May, 1865, p. 117, I recorded how once, by accident, I succeeded in growing Delesseria sanguinea in a deep and almost quite dark hole in a tank.

The shells of Murex from Weymouth not only thus abound with alge, as described, but are frequently met with rich in numerous parasitic animals-as Serpula and Sabellæ of several species, Sabellaria, Spio, and other things. The shells of living Nassa reticulata (Dog Whelk), found in the Baltic Sea, are usually covered with colonies of a little zoophyte-Coryne; but I have not seen English specimens of Nassa, thus infested. The shells of Buccinum, Purpura, Natica, and Fusus, when inhabited by their proper molluscs, are never grown over with any animal parasites, as far as I have had opportunities of seeing them; but when the same shells are occupied by hermit crabs (Pagurus), they -the shells are then often densely covered with colonies of another beautiful little zoophyte (Hydractinia echinata), except at that part of the shell which is dragged along the ground by the crab, and this portion is not only free from zoophytes, but is polished with the friction.

Last Sunday I had brought me a half-grown female living specimen of the edible crab (Cancer pagurus), the carapace measuring 10 c. 2 m. long, and 16 c. 4 m. broad. On this carapace has grown, and is still there, a living oyster (Ostrea edulis) measuring 8 c. 3 m. × 7 c. 7 m. This oyster is between four and five years old, the age of the mollusc being well known by its appearance, as it is a cultivated article of commerce, and a fixture during its life. Consequently the crab cannot have changed its shell during the existence of the oyster upon it, a period of from four to five years. But when younger, this crustacean (C. pagurus) exuviates much oftener. Thus, in our aquarium, on the 2nd of March, 1864, a small specimen, measuring 3 c. 3 m. x 2 c. 1 m., cast its shell, and when it appeared in its new coat it was 4 c. 4 m. x 2 c. 7 m. On February 28th, 1865, it again exuviated, and appeared with a carapace of 6 c. 9 m. x 4 c. 5 m. On April 14th, 1866, it once more changed its shell, and now the crab, which is still in the aquarium and doing well, is quite a portly fellow of 9 c. 8 m. x6 c. 0 m. These figures do not present to the imagination what the empty shell and the newly coated animal convey to the eye when the two are placed side by side, and unless one has seen the

operation as I have often done, it is difficult to believe that the comparatively large creature has emerged from the small case, especially after the lapse of a day or two, when the newly clothed creature has had time to get hard, and can be felt with the fingers to be so.

This article is already too long: if it were not so, I would describe the manner in which I have seen various crustaceans get out of their old shell, and what they do before and after the change. But this I must reserve for another time.

Zoological Gardens, Hamburg.

W. ALFORD LLOYD.

THE GREAT SAW-FLY (Urocerus gigas). THE other day I saw, for the first time, this fine

insect alive. My daughter called my attention to it on a new larch telegraph-post near Ditton, Cambridge. Having secured the captive, we came to the conclusion that it had as good a right to its life as ourselves, and put it back on the bark, where, after a few flights, it settled again, and began trying all the bare places on the bark for one to deposit its eggs. Hunching up its great body so as to bring the point of the sheath to the desired spot, it in vain tried to set its auger-like ovipositor to work. Again and again it failed, still trying as busily as ever, and then, finding that our lady friend could make no hand at it, I examined the instrument, and found it had grown to only half its proper length in this specimen.

Fig. 167. The Great Saw-fly (Urocerus gigas).

The black ovipositor in a perfect insect (we found a smaller one busily at work lower down the post) reaches to the extremity of the sheath; and the instinct of the creature induces it to bend the body so that the point of the sheath and the ovipositor together may make the first impression at the desired spot. The animal must have some means of judging