quite example of the Hippoboscidae

will serve as an excellent

can be found without difficulty upon almost any sheep ; but to get it away without damaging it is not a very easy task, the hooked and powerful legs grasping the wool as if with six pairs of pincers, and the insect pushing its way deeper and deeper in the fleece as it thinks itself in danger. While thus engaged in evading the pursuer, the Sheep-tick looks so very much like a spider that the French call it the Spider Fly.

The whole structure of the head and beak of this insect is very remarkable, and it is not very easy to trace the analysis of the various parts of the mouth. If one of these insects be examined with a microscope, the front of the head is seen to be furnished with two rather long, curved, pointed, horny plates, covered with bristles, between which lie the setae or piercing organs. Mr. Westwood thinks that these instruments are intended for the purpose of pushing away the hair of the animal on which the Fly is feeding, so that the setae may penetrate the more deeply into the skin.

It is evident that these projecting horny processes would be very much in the way of the Sheep-tick when it travels to and fro through the wool. If, however, the insect be turned over, so that the under surface can be seen, the mode in which this difficulty is overcome is at once evident. On the under surface of the thorax there is a deep pit, extending beyond the forelegs as far as the base of the middle pair of legs. When the head is bent downwards, the two horny projections, together with the piercing and sucking apparatus of the mouth, are sunk completely into the pit, so that nothing is presented to the wool but a perfectly smooth and shining surface which can easily glide between the fibres.

The colour of the Sheep-tick is yellow-brown, and the thorax and limbs are polished and granulated. The legs are remarkably strong, and the claws are jet-black and shining. In shape they very much resemble the incuiwed claws of the sloth, and the analogy between them is carried out in their action as well as in their form. Just as the hooked claws. of the sloth enable it to move with, great activity among the branches, swinging itself from bough to bough as easily as does a monkey, so do the similar claws of the Sheep-tick enable the insect to traverse the thick wool, among the fibres of

which it travels with a rapidity that seems scarcely possible in such a locality.

I never saw a sloth on a level or smooth surface, but it is well-known that the long and curved claws which are so useful among the branches, are absolutely impediments when the creature is on flat and hard ground on which its claws have no hold. Similarly, I And that whereas the common Flies can move about actively enough on glass, even though it be upright, the Sheep-tick is quite at a loss when placed on a plate or any similarly smooth substance. Under such circumstances it moves its legs with great rapidity, but does not succeed in making much progress, and the unwonted effect of its exertions seems to throw it into quite a fever of fright and anxiety.

This is one of the wingless species. It is so completely without wings that even the practised eye of the entomologist, aided by the microscope, can hardly detect the undeveloped rudiments of these organs. The insect, indeed, seems to be nothing but legs and abdomen, the latter being nearly flat and this shape being intended to serve a purpose which will round, presently be described.

LXXVI. Fig. 2 is given a figure of the Finch

On Woodcut Fly (Ornithomyia fringillaria). the right hand of the Fly, and at Fig. d, is drawn the

On under part of the head, so as to show the horny projections been mentioned in the description of the which have already Mr. Kirby remarks that he has himself suffered Sheep-tick. the attacks of one of the Omithomyise, which would from on his head, and driving their beaks into his persist in aUghting in catching two specimens, and found skin. He succeeded them to be Ornithomyia avicularia. of our present species is ochreous, changing in

The colour The head and thorax are shining some Hghts to green. and having a faint Une down the yellow mottled with bro^vn, The abdomen is dull green and hairy, middle of the back. and the claws jet black. The wings the legs are bright green, This is the smallest species of its are iridescent and smoky. small birds, such as the titgenus, and it is found on various and the robin. mouse, the yellow-hammer,

On Woodcut LXXVII. Fig. 1 is shown the insect which has been accepted as the type of its family. This is the too familiar Hoese-flt {Hippobosca equina).

This very plentiful and very unpleasant insect is an absolute pest to those who have to deal with spirited horses, especially when passing through woods. The Flies settle in numbers on

Hippobosca equina. 2. Stenopteryx hirundinis. a. Hippobosca equina, antenna. 6. Do., maxilla. c. Do., fore-leg. d. Stenopteryx hirundinis, fore-leg. c. Do., lip and tongue. /. Do., antenna. the animal, and cling so tightly with their hooked claws that they cannot be shaken oflf by any efforts of the aggrieved quadruped. They cluster round its eyes, get behind its ears, under the belly, and, if they can, creep under the tail. All the angry lashings of that organ do not in the least affect their flat and tough bodies, and the repeated pricks of their sharp beaks sometimes irritate a sensitive horse to such a degree that it runs away, in the vain hope of escaping its persecutors.

The life history of this insect is very remarkable.

Fortunately for horses, the Horse Fly is anything but prolific, producing its young in a mode which is, I believe, confined to insects of this group. The mother Horse Fly never lays more than one egg, but then that egg is a phenomenon. In truth, it ought not to be called an egg, having no more right to that title than the so-called ‘ ants’ eggs ’ which have already been described. The reader may remember that the eggs of certain Flies are hatched in the body of the parent, so that they are deposited in the larval and not the egg state. The Hippobosca goes a step further. The egg, as it appears to be, is no egg at all, but the skin of the larva, within which the pupa is formed, so that the young Hippobosca is already a pupa when it enters the world.

When first produced, the puparium (to use the scientific term) is white ; but it soon darkens, and becomes quite hard and tough. If it be opened carefully, within it may be found the pupa, an odd-looking, crab-like being, with the legs tightly folded over the body. When the time comes for the assumption of the perfect state, it throws off the pupal skin, which it leaves within the puparium, pushes off the end of the case in which it had resided, and emerges as a perfect insect.

The chief points in the external anatomy of this insect are given on the same Woodcut. Fig. a represents one of the separated from the head. Fig. h is the part of the antennae mouth containing the diverging horns which Irave already been mentioned, and Fig. c represents one of the fore-legs, with its very powerful thigh, and its black, incurved claws.

At Fig. 2 of the same Woodcut is seen the Swallow Fly so called because it is found almost {Stenopteryx hirundinis), on the swallow tribe. The generic name is formed exclusively two Greek words signifying ‘ narrow-winged,’ and is very from as may be seen by reference to the illustration. appropriate,

Mr. Kirby mentions that this Fly sometimes attacks human : — ‘ One found its way into the bed of the Eev. E. beings where it first, for several nights, sorely annoyed a Sheppard, friend of his, and afterwards himself, wdthout their suspecting the culprit. After a close search, however, it was discovered, in the form of this Fly, which, forsaking the nest of the

swallow, had by some chance taken its station between the sheets, and thus glutted itself with the blood of man.’

Mr. Sheppard remarks, as a reason for this dereliction of their appropriate food, that no sooner does life depart from the bird that these Flies infest, than they immediately desert it and take flight, alighting upon the flrst living creatui'e that they meet with ; which, if it be not a bird, they soon quit, but, as it should seem from the above facts, not until they have made a trial how it will suit them as food.’

The fore-leg of this insect is shown at Fig. d, the lip and tongue at e, and the antenna at /. These organs should be compared with those of the previously described insects, as by their means identification becomes easy.

The generic name of the insect represented on Woodcut LXXVIII. Fig. 1 is formed from two Grreek words, signifying ‘ blood-devourer,’ and is very appropriate. Its scientific name is Hcemoboi^a pallipes. I believe it is not common enough to have any popular name.

The general colour of this insect is shining greenish-yellow, clouded with brown. The eyes and claws are black. Beneath, the thorax is boldly punctured, and covered with short and strong hairs. The wings are nearly transparent, with yellow nervm'es, and slightly ciliated on the costal margin. The insect is found in the New Forest, attacking indiscriminately any kind of quadruped.

The points in which this insect differs from those which have hitherto been described are shown in the illustration. Fig. a gives the front view of its head, which, as will at once be seen, is very different from that of the other Hippoboscidse. The wings, too, are very much larger in proportion, and have a few very distinct nervures. The antenna is feathered, and the fore-leg, as shown at b, is short and strong. The peculiar form of the mentum, with its array of bristles, is shown at c.

The second family of this group, or Nycteribiids, has the head very small and set on the back or upper part of the thorax, and it cannot be bent down into a cavity of the under surface of the thorax, as is the case with the preceding insect. They are without wings, but Mr. Westwood thinks that a pair T T 2

of curious little organs, like semi-circular combs, which are at the base of the intermediate legs, are the representatives of wings. The thorax is flat, and seems to be made almost entirely of the first joints of the legs, which are very long in proportion to the size of the body.

There is a peculiarity in the legs of these insects which is worthy of notice. The basal joint of the tarsus, instead of

Htemobora pallipes. 2. Nycteribia Latreilli. a. Hasmobora, front vieTT.

b. Do., leg. c. Do., mentum. d. Nycteribia, leg. e. Do., head, side view.

short, as is usually the case, is very long, and being small and so thick, is quite as long as the tibia itselt. in fact, though not from the rest of the limb, it would e Indeed, were it separated tibia. The claws, too, are so large certainly mistaken for the observer of the sting of the scorpion. that they remind the the legs is shown at Fig. d of Woodcut LXXVIII. One of LXXVIII. is shown the insect popularly caflea

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