last segment bearing two lengthy, cottony filaments, and terminated with at stout style, which is the external organ of reproduction. The males of the different species, as far as observed, are somewhat similar in appearance and size. The general colour is a light brownish-yellow, which contrasts strongly with the prominent dark eyes. The Female Insect. The colour of the adult female is either brown or yellow, and in the earlier stages white. In shape it has a striking resemblance to the schoolboys battered peg-top; it is soft and much wrinkled, the abdomen more or less incised. The head and prothorax appear as one segment; supporting the mouth, antennæ and first pair of legs; upon the ventral surface, and separating the anterior portion from the meso-thorax is a deep transverse curved furrow, forming a distinct chin below the mouth. This "facial" furrow is an arc of different dimensions in the various species, being more acute in some than others. Below the furrow, and between the intermediate pair of legs, is a deep depression generally transverse and oblong, sometimes square or constricted, and at times obconical; the depression always shallows up into the facial furrow. The abdomen is conical and tapers more or less acutely, the last three or four segments being of a hard horny character; the posterior margins of all but the last segment usually bearing dorsally an irregular row of conical thorn-like spines. The last segment carries two apparently tubular appendages which give it a cleft appearance; in some instances these "points" are themselves bifid, terminating in two distinctly tubular organs which may yet be found to perform similar functions as the honey-dew producing organs of the Lecanids. The antenna and six legs are almost rudimentary; the mouthparts comparatively small but no doubt capable of use. The softer portion of the body is covered with hairy tubular spines and peculiar spinnerets which, in some species, have the appearance of rings of minute circles enclosed by simple concentric rings. The insect is coated with a secretion of powdery white meal. The Larvæ. The larva of all the Brachysceles are very similar in appearance, and afford no sufficient characteristics for the determination of species. They are active, of a bright yellow colour, flat and elliptical in shape; the legs are long and well developed, bearing several spines and a pair of digitules; the antennæ are slightly hairy, about seven joints; the eyes are a brownish-red and large, the edge of the body surrounded with a fringe of stout alate spines; the "wings" of the spines are thin and transparent, and soon become broken off. Shrader and Froggattt both speak of these insects as "digging" or "mining," but this is obviously an error. How can insects with suctorial mouths, and legs unformed for such purposes, either "dig" or "mine"? Galls of the Male Coccid. These are invariably short cylindrical tubes, two to six lines in length, generally growing upon the leaves; they are mostly of a purple-claret colour, but often brown or green. Some are simple tubes with a notched rim at the summit, others have the rim dilated forming a saucer-like top. The male gall *Proc. Ento. Soc., N.S.W., pp. 4, 5. Vol. I (1866). + Trans. Linn. Soc., N.S.W., p. 356. Vol. VII, 2nd Series (1892). of B. rugosa, Froggatt, is emerald green, cylindrical, constricted at the base stout with thick soft walls, the apex truncate; length, four lines; breadth, one line. In several species these male galls grow upon the female gall; B. Munita, Shrader, has the males separate and springing from the horns; in B. phratrata, Shr., B. Thorntoni, Frogg., and B. nux, they are congregated together in a cup-like growth. This growth expands like a flower, and is, I am afraid, rather inaptly described by Shrader as a cockscomb, and as a mushroom-like growth by Froggatt. There is generally only one cup-growth attached to a female gall, but B. nux, as a rule, has two, and often three. They are attached at one side of the summit of the female gall, which they often exceed several times in size. The Female Galls Exhibit a great variety of forms, which are the easiest means of distinguishing the different species, varying in size from one-half to six or seven inches in length. In the shape there is as great a variety as in the size; many of them resemble conc-like fruits, others nuts and fruits, whilst the lateral growths of B. duplex are not unlike leaves. Occasionally growing on stalks, they more often sit close upon either the twigs, branches, or leaves, from which they spring. The Formation of Galls. The number of various gall-making insects which have the remarkable power of diverting the forces of nature, as represented in the growth of a plant, to their own advantage, has given rise to a deal of speculation and experiment to discover the inherent element or property possessed by the insect by means of which it operates. Up to the present we can go no further than to say that the galls are due to an irritation set up by the insect, yet each individual species must have some peculiar properties or how would we find such wildly differing results when in their initial stages the producers are as alike as the two proverbial peas. Mr. Tepper asserts that the larvae always select an embryo-bud, and by the context he evidently wishes an undeveloped but true bud to be understood. This is, however, not the case; it may hold good in some instances, but certainly not in all. Whether upon stem or leaves the gall-growth originates from the cambium ring; the developmental activity of the cells is released by the insect, and a shoot forms over the growth of which the animal maintains direction. This is proved by the cessation of growth when the coccus, in a young stage, is killed by parasites. The rudimentary gall, according to Dr. Adler, draws its nourishment from the surrounding tissue; later on, however, processes are driven into the gall from the spiral vessels of the cambium ring which form a new element to assist in its development, and it thus becomes an independent structure, having individual powers which regulate its shape, position, &c. These remarks, whilst referring to galls formed by wasps, apply equally to coccid galls. Previous Notices on Brachysceles. The first notice of the genus appeared in Vol. I of the Trans. Ento. Soc. N.S.W., in which several descriptions are published by Mr. H. Shrader, of Sydney. A similar paper from the same author appeared shortly afterwards Alternating Generations: A Study of Oak Galls and Gall Flies, by Hermann Adler, M.D. Translated and edited by Chas. R. Stratton, F.E.S., &c., Oxford, 1891. in a German publication.* Mr. Shrader formed the genus and named it Brachyscelis. The second account, from the pen of Mr. W. W. Froggatt, of the Sydney Technical Museum, appeared in Vols. VII and VIII (2nd series) of the Trans. Linn. Soc. N.S.W. Mr. Froggatt publishes nine new species of Brachysceles, and also several descriptions of insects belonging to Shrader's allied genera, Opisthoscelis and Ascelis. An account of the genus, with descriptions of some gall-growths, appeared in Vol. XVII of the Proc. Royal Society of South Australia, by Mr. J. G. O. Tepper. The galls are classified according to the "direction of the axis of the gall." The classification is a distinct innovation, and may be intended to apply to galls and tumours formed upon plants by any insect agency. As far as the genus Brachyscelis is concerned, the direction of the axis of the gall is not constant enough to merit more than passing consideration. In his criticism of Mr. Tepper's paper, Mr. Froggattt asserts that the growth named regularis is synonymous with B. pedunculata; unalis with B. Shraderi, and strombylosa with B. crispa. While not denying that the gall called strombylosa is similar, if not identical, with that formed and inhabited by the insect B. crispa, I cannot agree that the others are, as neither Teppers drawings or descriptions tally with the galls of B. pedunculata or B. Shraderi. Personally I regard it as decidedly wrong to name an insect without describing or perhaps even seeing it, and for that very reason refrain from specifically naming the maker of the pretty and interesting gall figured on plate III, figs. IV to VII, The following descriptions which I have prepared are intended to assist in the classification of the insects from the characters of the tapering abdomen. It is with extreme regret that I have to draw attention to the name bracketed after each species. The specific name of each insect was originally chosen by the late Mr. Olliff and myself, and, had my friend lived, the descriptions would have been published conjointly: his death deprives them of much genuine value. They are, however, presented as the result of careful and original work, and as a poor memorial of my late chief, at whose suggestion the work was taken in hand immediately prior to his sudden death. Brachyscelis pedunculata, n. sp. (Olliff, M. S.), (Pl. I, figs. i to v), ? [see Note, p. 213] coccus (Pl. I, fig. iv), brownish yellow, four last abdominal segments and appendages deep brown; elongated, head and thorax somewhat cylindrical; abdomen tapering; last segment of the thorax separated by a deep incision from anterior portion; length, 12 lines; breadth, 3-4 lines across broadest part of thorax; clothed with numerous hairy, tubular spines, conspicuous upon the first four segments of the abdomen. Dorsally, and situated in a line upon the hinder margin of each abdominal segment except the last, are conical thorn-like spines. These are always greater in number upon the posterior segments, varying from two to four upon the first to from seven to ten upon the sixth. (Pl. I, fig. iv b, c). The last segment of the thorax occasionally bears two or three similar spines. The body-wall is punctured thickly with scattered, floriform spinnerets (Pl. I, fig. iv a), which, however, in the thicker abdominal portion appear as simple pin-hole orifices. The "facial" furrow which divides the head and prothoracic segment from the meso-thorax is angular and deep, making the "chin" prominent. Median * Verhandlungen der K.K. Koologische-botanischen Gesellschaft in Wien, Jahrg. 1863, p. 189. Taff iii. + Trans. Roy. Soc. S. Aust., Vol. XVIII, p. 95 (1894). |