Abdomen quite bare.

Abdomen five or six-segmented, flat, wings broad and large-triangular: Phasing.

Abdomen four-segmented, globular, wings of normal shape, rather small: Gymnosominæ. Abdomen pubescent, large spines nearly always present.. Abdomen five-segmented, long-genitalia very prominent.

Fourth longitudinal vein meeting third some distance from edge of wing, fifth meeting fourth much beyond middle of first post. cell: Ocyptering. Fourth longitudinal vein meeting third nearly at edge of wing, fifth meeting fourth before centre of first post. cell: Phanina. Abdomen four-segmented, conical, genitalia not prominent: Tachinina.

The principal genera are Echinomyia, Dumer, Nemoraa, Desv., Exorista, Mg., Tachina, Mg., and

Exorista vulgaris, Fln., is a tessellated black and grey fly, subject to much variation; wings clear; face silvery-grey, with a central broad brown band; antennæ large, long, black; legs black; alul large, white; long 7-8 mm. Most of the genera are represented by two or three species only.

Nemorca occurs chiefly in woods.

Gymnosoma, Mg., and Clytia, Desv., frequent the carrot plant.

In Myobia, Desv., and Metopia, Mg., the g lays her eggs on the dead insects brought into Hymenopterous nests as food.

Phorocera, Desv., but the state of our knowledge of the group is at present highly unsatisfactory.

Echinomyia grossa, L., is one of the largest British flies, and is a large black bee-like fly covered with soft black hair; face, front and back of the head yellow, with short bright golden pubescence; antennæ tawny, tips black; legs black; wings pale grey, tawny at base and on the fore-border; long 12-15 mm.

Olivieria lateralis, F., abdomen tawny, with a central dorsal black stripe enlarged towards the tip, and covering the whole of the last segment; thorax black with indistinct grey stripes; face and front silvery grey; antennæ and legs black; wings pale grey, brownish on fore-border; long 7-8. Common in long grass.

Fig. 142.-Estrus, L.

Tachina, Masicera, Exorista, Nemorca, Echinomyia, and others are known to be parasitic on Lepidoptera, Serville thinking that Nemorca is also parasitic on Lepidopterous pupa.

Gonia, Mg., is represented by five species, none common; the face is very broad.

Trixa, Mg., somewhat resembles Sarcophaga; three species, larva unknown.

Alophora hemiptera, F. Pauz. lxxiv. Echinomyia ferox, Pz., Pauz. civ. Trixa variegata, Mg., Wlk. ii. Pl. xii. 3. Gymnosoma rotundatum, L., Wlk. ii. Pl. xi. 6. Ocyptera brassicaria, F., Curt. 629.

(2.) Dexina.

This small group is closely allied to the Tachininæ, and calls for no special mention; about twenty

species are British, nearly all representing a different genus each; of Dexia we have five species. The larva of the Dexina are chiefly parasitic on Lepidoptera; the flies frequent flowers and dry, warm spots, and are often found in woods.

In Desvoidy's splendid work on the "Myodaires," he gives a lengthy list of the species of Tachininæ and Dexine that are known to be parasitic, with the species of insect infested.

As a rule the abdomen is longer and more pointed in this group than in the Tachinine, and as in that group the legs are brittle and easily become detached from the body.

Prosena siberita, F., Curt. 665. Thelaira leucozona, Pz., Pauz. civ.

(3.) Sarcophagina.

Dr. Meade, a few years ago monographed the British species of this group, which number about twenty, all (with one or two exceptions) being closely allied and exceedingly difficult to identify.

They breed in decaying animal matter, occasionally in dung. The imagos usually have tesselated black and grey abdomens-with strong spines towards the tip. The thorax is usually longer than it is broad.

Cynomyia mortuorum, L., is a large, bright blue fly which breeds in the putrid corpses of animals, generally dogs; appearing in April and May. The face is bright golden yellow; the legs black; wings nearly clear. It is not common here, but is frequently met with on the Continent; long 8-12 mm.

Sarcophaga, Mg., is a genus of flies, in which the thorax and abdomen are divided into tessellated squares, the wings are pale grey, the legs black; and the thorax, abdomen, and legs covered more or less with spines, the number, length and position of these spines being important specific characteristics.

S. carnaria, L., the commonest species, is known. as the "flesh-fly."

In some species the extreme tip of the abdomen is bright red. The in this genus is viviparous, 20,000 larvæ having been found in a single specimen.

(4.) Muscina.

The flies of this group are the greatest scavengers of the order, the larvæ living in decomposing animal matter and devouring nearly all the fleshy part of the carcase. Sometimes they breed in dung.

About thirty species are British, many very

common.

The principal genera may be separated thus :

Proboscis horny, projecting horizontally, prominent: Stomoxys, Geoff.

Proboscis soft, vertical, not prominent.

Fourth longitudinal vein at its bend upwards not forming
a sharp angle.

Middle tibia spined along its length: Mesembrina,
Mg.

Middle tibia spined only at tip: Cyrtoneura, Mcq. Fourth longitudinal vein at its bend upwards forming a sharp angle.

L. Cæsar, L., and L. cornicina, F., are the two most common species, appearing everywhere; the latter being easily known by its bright green face. These flies are sometimes known as green-bottles." Calliphora erythrocephala, Mg., is the common meat-fly or "blue-bottle; a closely allied species, C. vomitoria, L., has a red beard. The progeny of this fly is said to amount to 500,000,000 in twelve months; and Mr. B. Lowne, who has made this species a study for many years, asserts that in the imago " not one structure exists as it exists in the maggot." Musca domestica, L., is the common house-fly. Black and grey, with rather tawny sides to the abdomen; antennæ, legs, and eyes black; wings clear; thorax black, with grey stripes; face silvery; long 5-7 mm.

Mesembrina meridiana, L., is a rather large black hairy fly, with black snout and golden yellow cheeks; black mouth and eyes, black legs, grey wings, tawny at the base and along the fore-border; not uncommon; local; long 10-11 mm.

Stomoxys calcitrans, L., is easily recognised by its strong, prominent proboscis. About the size of M. domestica, the abdomen being greyish with black markings; usually found on sunny days on leaves and wooden posts; it follows horses in numbers, and causes much irritation by its bite; long 6 mm.

Cyrtoneura stabulans, Fln., greyish, with pale brown reflections, larger tham M. domestica, common everywhere, especially in houses.

It has been bred from shallot, but the species in all probability breeds in a variety of substances.

Anal vein nearly reaching border of wing.
Arista feathered: Hydrophoria, Des.

Arista pubescent or bare: Anthomyia,
Mg.

Anal vein very short, curved towards the axillary vein: Homalomyia, Bouché.

Alulæ small; scales of equal size.

Arista feathered: Hylemyia, Des.

Arista pubescent or bare: Chortophila, Mcq.

Limnophora, Des., comes chiefly from Scotland. Hydrotaa dentipes, F., is a dark grey fly, with greyish reflections; pale brown wings; black legs and silvery cheeks, and is common in most parts; variable; long 9 mm.

Drymeia hamata, Fall., may be easily recognised by its strong hooked proboscis.

Hylemyia strigosa, F., is a bristly grey fly, the dorsum of the thorax being pale brown, distinctly marked off from the lower part of the thorax ; abdomen grey, with a dorsal and three transverse black stripes; face silvery seen from above, black viewed from below; mouth and antennæ black; eyes reddish-brown; wings pale grey; legs blackish, tibiæ more or less dark tawny; common, especially in woods; variable; long 6 mm. One species (H. coarctata, Fall.) damages the wheat crop whilst in the larval state, attacking the stalk.

Anthomyia radicum, L., ♂, is a small black fly, breeding in cabbage and other like plants; abdomen dark grey, with a dorsal and four transverse black stripes; face and legs black; wings pale grey; eyes often with a silvery border; very common on low herbage and in London gardens ; long 4 mm.

A. sulciventris, Zett., is also common everywhere, the is a nearly black fly, with unmarked abdomen. The is greyish-black, with unmarked abdomen.

Caricea tigrina, F., common in long grass; bristly, grey with rows of black spots on the thorax, each giving forth a bristle, and with four brown spots on the abdomen; legs black with tawny tibiæ; face grey with a broad central stripe; eyes and antennæ black; wings pale grey; variable; long 5-6 mm.

Chortophila, Mcq., an extensive genus of small flies allied to Anthomyia, many being tolerably common; some of the species being parasitic on wild bees, Dr. Meade having taken them in the nests of the latter.

Homalomyia canicularis, L., is very common in houses; blackish-grey; abdomen tawny, divided by a dorsal and two transverse lines into six squares, tip blackish; face silvery white, with a central black stripe; wings pale grey; legs blackish; variable; long 4-5 mm. The males of this genus hover together in the air in a group, sometimes for hours together, and are often seen in rooms in early morning hovering below the centre of the ceiling or near the windows.

This species and another of this genus have been bred from the human body.

Hylemyia coarctata, Fln., in the larval state does considerable damage to the wheat crop.

The larva of Canosia, Mg. (allied to Caricea), lives in cow-dung.

Over a dozen genera are represented by only one or two species each. In several of the less developed genera the eyes are widely separated in both sexes, thus approaching the acalypterate Muscida, from which they are scarcely structurally distinct.

Plates are not of much value in this group, except to illustrate genera or very characteristic species.

Hydrotea ciliata, F., Curt. 768. Lispe tentaculata, Deg., Walk. ii. Pl. xii. 1. Anthomyia pluvialis, L., Walk. ii. Pl. xii. 2. Polietes lardaria, F., Walk. ii. Pl. xii. 9. Drymeia hamata, Fln., Walk. ii. Pl. xii. (To be continued.)

12.

A NEW SPECIES OF DASYDYTES-ORDER GASTROTRICHA.

THIS

HIS Order of the mighty worm-alliance seems to have attracted very little, if any, careful observation in this country of late years, although both on the Continent and in the United States a great amount of attention has been devoted thereto. Quite recently, in 1887-8, Mr. A. C. Stokes added greatly to our knowledge of the American forms, describing in his papers in the "Journal de Micrographie," numerous new species of Chatonotus and other genera; while in 1889, Dr. Carl Zelinka published an exhaustive monograph of the group ("Die Gastrotrichen," in "Zeitschr. f. wiss. Zool.," xlix., Part 2), in which all Stokes' recent species are included, and to which admirable work I can confidently refer British microscopists desirous of extending their acquaintance with these creatures.

In our own country, Mr. T. Spencer described, in "Journ. Quekett Micro. Club," January 1890, under the name of Polyarthra fusiformis, an animal which, however, is not a rotiferon, but (as pointed out by me in the same Journal, January 1891) clearly referable to the genus Dasydytes of the Gastrotricha. This must evidently be known in future as Dasydytes fusiformis, Spencer; it is a pretty and curious little creature, very distinct from any previously described.

In all probability, many or most of the species recorded from the above countries, are also common to Britain, if observers would but search systematically for them, and place on record (such forms as they may chance to meet with. It is for this purpose of awakening interest, and so helping to increase our knowledge of our indigenous Gastrotricha, that this communication is written.

In November, 1890, whilst searching for Rotifera, I came across, in water from a pond near Leytonstone, Essex, some specimens of a Dasydytes which

the skin are more or less visible, crossing the neck. The head is large and wide, three-lobed in dorsal aspect, the lateral lobes prominent like puffed cheeks; the width of the head is nearly twice that of the neck, and about three-fourths that of the body at its widest part. Both head and neck are usually considerably flattened, excepting the lateral head-lobes, which are somewhat globose and thicker than the central region of the head. The trunk is not at all flattened, appearing circular in optical cross-section.

The head is covered on all its surfaces, dorsal, lateral, and ventral, with numerous long vibratile cilia, directed backwards.

The body is furnished, on its lateral surfaces, with a few rather short, very thin and delicate, somewhat appressed bristles, apparently arranged in about three longitudinal rows on each side, though this is a point difficult to determine. I do not think any bristles occur on the dorsal surface proper. These setæ occur also on the sides of the neck, and, in side view of

Fig. 143.-Dasydytes bisetosum.

does not appear to be identical with any member of this genus included in Dr. Zelinka's recent monograph, above referred to. Some half-dozen indivi duals were seen in all, and afforded me opportunity of making the following observations, and of securing a fairly accurate sketch of the animal. I propose to call this Dasydytes bisetosum.

The body is plump and of oval outline when seen dorsally, rounded posteriorly, and of course without any caudal fork; anteriorly, the trunk narrows to the neck, which latter is very distinctly marked off from the head. A ccuple of transverse wrinkles in

Fig. 144.-Dasydytes bisetosum.

the animal, are seen to be directed dorsally and posteriorly; none are nearly so long as the terminal caudal bristles to be described. The animal's ventral surface is longitudinally furred with active cilia, like all the members of the Order. The body is rounded behind, and has a terminal projection, convexly truncate, from which are given off two long, thin and delicate setæ, quite one-third the total length of the animal's body and head, set wide apart at their base, and carried parallel or with their tips in contact. It is on account of these two conspicuous tail-bristles, which serve by their great length to distinguish this new form from its allies, that I have selected the specific title "bisetosum" for the

creature.

The mouth is a permanently projecting tube, surrounded by a ring, at the extreme front of the head. It is continued into a long oesophagus, about one-third the total length of the animal, having a narrow but distinct, straight lumen, and very thick walls, on which I could detect no cross-striation.

The gullet terminates, at the point where the neck passes into the trunk, in a long straight stomach, running along the ventral side of the body-cavity, and crowded with colourless food in pellets; this is continued, without any visible constriction, into the intestine, and ends in the anus just in front of the rounded posterior extremity of the trunk. I could not determine the presence of the water-vascular canals and contractile vesicle; almost; certainly these exist, but are exceedingly difficult to observe.

Dorsally to the stomach is situated a fairly large, colourless body, exhibiting a central nuclear vesicle; this body was formerly thought to be the ovary, but Dr. Zelinka has shown that the true ovaries in the Gastrotricha are paired organs placed near the venter, one on each side of the intestine, (thus corresponding in position with the paired ovaries of the family Philodinadæ of the Rotifera). The large dorsal body is a developing ovum; whether this is contained within an oviduct having extremely delicate membranous walls, or simply lies freely in the perivisceral cavity, is doubtful; as also is its mode of exit from the body.

The creature swims actively with an even gliding motion through the water; in no case did I observe any jerking or springing, the weak body-spines being probably useless for such a mode of progression.

The head is often freely moved up and down upon the neck, but has not the constant drooping appearance (in side aspect) noticeable in D. fusiformis. The lateral lobes seem capable, to some extent at least, of being protruded or retracted at the creature's will; at certain times, the outline of the head appeared quite conical, or very faintly five-lobed (cf. the figures), while at others, the same animal presented the distinctly three-lobed outline of the head already described.

The present species approaches in its general outline D. longisetosum (Metschn.), but is at once separated from the latter by the relative lengths of the body and caudal bristles. The latter are, in longisetosum, shown much less than half the length of the lateral body-setæ (which are described as "very long and stout,") and altogether lack the conspicuousness they attain in bisetosum. The present form is also nearly twice the size of Metschnikoff's species, and other differences exist which I think fully justify me in regarding bisetosum as specifically distinct.

The entire animal is quite colourless; length, excluding caudal setæ, about 4 inch.

In conclusion, the same pond has furnished me, on other occasions, with specimens of Dasydytes fusiformis, Spencer, and Lepidoderma rhomboides, Stokes, (the latter only recorded, hitherto, from Trenton, New Jersey), while at Chingford I have met with Dasydytes goniathrix, Gosse, and D. fusiformis, Spencer. Within the last few weeks, at Oakley, in Bedfordshire, I have taken Chatonotus Schultzei,

SCIENCE-GOSSIP.

WE are pleased to observe that an old and valued correspondent of SCIENCE-GOSSIP, and an ardent naturalist and botanist, Mr. T. D. A. Cockerell, has been appointed Curator to the Museum, Institute of Jamaica, Kingston (which will henceforth be his address). The institute is to be congratulated on having selected such an efficient curator.

THE great engineer, Sir John Hawkshaw, died in his eighty-first year on June 2nd.

PROFESSOR ROBERTS-AUSTEN has discovered the most brilliant-coloured alloy yet known. It is of a rich purple colour, and has bright ruby tints when light is reflected from one surface to another. It consists of 78 per cent. of gold, and the rest aluminium.

THE science of geology has received royal recognition. The Director of the Geological Survey of the United Kingdom has been made a Birthday Knight, and is now Sir A. Geikie.

PROFESSOR LEIDY, the well-known American naturalist, author of the "Rhizopods of North America," is dead.

AT a recent meeting of the Linnæan Society, Mr. Robert Deane exhibited specimens of the rayless daisy, said to grow abundantly near Cardiff. Will some reader there send us a specimen?

WE have received the "Report of the Felsted School Nat. Hist. Society for 1890." It displays a healthy, active, and intelligent love of natural science, and indicates a state of things the author endeavoured to realise in "The Playtime Naturalist."

THE latest Bulletins issued by the U.S. Dept. of Agriculture are Nos. 7 and 8 of "Insect Life," and No. 24 "The Ball-Worm of Cotton," by F. W. Neally.

BISHOP MITCHINSON'S papers in "Nature Notes," on "The Distribution of Rare Plants in Britain," are very suggestive.

WE are pleased to call attention to a highly important brochure by the Rev. H. A. Soames, F.L.S. (London: L. Upcott Gill), on "The Scientific Measurement of Children." The author rightly