INSECTA. 
630 
Peleeocera, Hoflf., is unknown to me, but is at once distinguished from all with the antennae shorter than the 
head, by the short, thick seta of the antennae. 
The sucker of all the other Athericirae is only composed of two setae, of which the upper represents 
the lahrum, and the lower the tongue. 
These Athericerae form three small tribes, which correspond with the genera (Estrus and Comps 
of Linnaeus, and with that of Musca of Fabricius, as at first proposed by him. 
As Stomoocys and Bucentes are connected with the last of these genera, we shall commence with the 
tribe (Estrides, Latreille, which is composed of the genus 
(Estrus, Linn., — 
Well characterised by possessing, in the place of a mouth, only three tubercles, or but slight rudiments 
of a proboscis and palpi. 
These insects have the appearance of large meat-flies, very hairy, their hairs being generally coloured 
in rings, like Humble-bees. Their antennae are very short, each inserted in an excavation below the 
forehead, and terminated by a rounded palette, bearing on its back, near the base, a simple seta ; the 
wings are generally apart ; the alulets large, and hiding the balancers ; the tarsi are terminated by two 
ungues, and two pulvilli. 
These insects are found but rarely in the perfect state, the time of their appearance being very 
limited. As they deposit their eggs on the bodies of various herbivorous quadrupeds, it is in woods 
and pastures frequented by these animals that they are to be sought after. Each species of (Estrus is 
ordinarily parasitic upon a single mammiferous animal, selecting, as the situation for its eggs, that part 
of the body which is best fitted for the larvae, which either remain in that particular situation, or are 
passed from thence to a more favourable place of developement. The Ox, Horse, Ass, Eein-deer, Stag, 
Antelope, Camel, Sheep, and Hare, are the only quadrupeds hitherto known to be subject to the 
presence of the larvae of (Estri. These animals appear to have a strange dread of the insect, when it 
seeks to lay its eggs upon them. 
The nature of the abode of these larvae is of three kinds, which may be distinguished as cutaneous, 
cervical, or gastric, according as they reside either in tumours formed in the skin, or in some parts of 
the head or stomach of the animal destined to support them. The eggs, whence the larvae of the first 
kind are hatched, are placed by the parent fly beneath the skin [of oxen, &c.], which it [is stated by 
some authors, including Latreille, but evidently erroneously,] to pierce with its ovipositor, composed of 
four tubes, entering into one another, and armed at the tip with two hooks, and two other pieces ; this 
instrument is formed of the terminal segments of the abdomen. These larvae, called taons by the 
French peasantry [and or worm/s by the English], have no need to change their situation, 
finding themselves, as soon as born [or rather as soon as they have buried beneath the skin], in the 
midst of a purulent humour, which serves them for nourishment. The eggs of the other species are 
merely stuck upon various parts of the body, either close to natural and internal cavities, into which 
the larvae easily penetrate, and there fix themselves, or where the animal is in the habit of licking itself, 
whereby the larvae are carried by the tongue into the mouth, and so pass to the place [in the stomach] 
destined to receive them. It is thus that the Sheep Bot-fly places its eggs at the inner edge of the 
nostrils of that quadruped, which becomes agitated, stamps the ground with its fore feet, and hurries 
away with its head to the ground ; the larva insinuates itself into the maxillary and frontal sinuses, 
and fixes itself to the internal membrane with which they are lined, by means of two strong hooks 
with which its mouth is armed. It is thus, also, that the Horse Bot-fly deposits its eggs, without 
settling, by hovering in the air at intervals over the inner part of the legs, at the sides of the shoulders, 
and sometimes on the withers. (Estrus h(Bmorrhoidalis, the larva of which also lives in the stomaeh of 
the Horse, places its eggs upon the lips ; the larvse, attaching themselves to the tongue, pass by the 
oesophagus into the stomach, where they subsist on the humour secreted by its inner membrane. They 
are generally found round the pylorus, and rarely in the intestines. They often exist in great numbers, 
hanging like a bunch of grapes : Mr. Clark, nevertheless, considers that they are rather serviceable than 
otherwise to the Horse. 
These larvse have, in general, a conical form, and are destitute of legs. Their body is composed of 
eleven segments, exclusive of the head, furnished with small tubercles and spines, often arranged in 
bands, and which facilitate their progression. The principal organs of respiration are situated in a 
