The Posterior Coxæ are only conspicuously enlarged in some particular species (dung beetles). There are two of them placed on the sides of the breast next to the abdomen, under the hinder thighs. In some they are placed remote and distinct from it, in others they lie close; being moveable in some, in others they are fixed. The use of these parts we are ignorant of.[[19]]
The Abdomen consists of a number of annuli or rings, and contains the greatest part of the intestines and other viscera; being united to the trunk, and formed with holes on the sides, through which the insect breathes.
The Limbs comprehend the TAIL, LEGS, and WINGS, with their cases.
The Tail is placed at the extremity of the abdomen; and in some is furnished with a sting, in others it is armed with a pair of forceps; sometimes with a single bristle, sometimes with a double one; in some with a pair of claws like a crab, in others like a fork.
The Legs include the coxæ, trochanters, femora, tibiæ, and tarsi; the latter consisting of two, sometimes of three, four, or five articulations. In some the fore ones resemble a crab's claws. Some are furnished with spines, others are smooth and plain. The hinder ones are formed for running, leaping, or swimming.
The Wings, being always two or four, are either plain or folded, erect or open, lying flat or inclining downwards, &c. In some they are dentated or scolloped; and some are furnished with two projections like tails. They are also membranaceous, reticulated, or transparent, and frequently adorned with beautiful colours. In some they are curiously folded within two crustaceous cases, that are either smooth or rough, striated, furrowed, punctated, &c. in some these cases are soft and flexile, in others hard like horn; the Hemipterous are partly soft and transparent, as in Plate [49]. Fig. 2. and partly opake and hard, as in Plate [42]. Fig. 1. Plate [43]. Fig. 2. and Plate [45]. Fig. 5.
It is necessary to observe, that I have not been so prolix and explanatory in the foregoing definitions as I should be, if I intended to arrange the figures under their respective classes, or establish any system for doing so; I have explained no more terms or parts than what are sufficient to enable the reader (if he is not an adept) easily and clearly to understand the descriptions. It is likewise necessary to mention, that I have given English names to most of the parts, where I could do it with the necessary propriety for serving this particular purpose; and where I could not substitute an English word, that was apposite and significant, I have preserved the Latin one, as used by Linnæus and others. Thus, for instance, the term palpi I would have altered, if I could have found an English word that conveyed the same idea; but not easily finding one, I have kept to the original. I have not forgot the terms mustachios, whiskers, &c. which I might have used in its stead; but as these parts in many insects bore no analogy or resemblance thereto, it being in a great many of them like a short jointed filament or thread, I rather chose to preserve the Latin one. The same practice I have observed with the term antennæ. For though feelers is the general explanation given to this word, I could not prevail with myself to use it. The reason is, because these animals seem to have a power of applying these parts to purposes different from that of feeling. By the antennæ they are capable of distinguishing and perceiving, as well as feeling; and I am strongly inclined to believe, it is by them the males are capable of discovering the females at a great distance. It is certain their powers of perception are very obvious and remarkable, which, by close observations, we may soon discover; and unless we allow them capable of smelling without nostrils, I do not know what parts they exercise, or by what means they so readily discover, not only their females but their respective kinds of food, the places proper for depositing their eggs, &c. The male moths appear to have this faculty of discovering their females in a greater degree than most other insects; for there are but a very few, if any, belonging to this genus, whose females pass the first night after they quit the chrysalis without coupling with the males; owing to unconquerable desire in the latter, and the strong effluvia or scent emitted by the former for attracting their mates. Every adept is fully acquainted that a female moth, known by the name of the Egger (Phalæna Quercus of Linnæus), taken into the fields the first day it is hatched, will most certainly (though shut up in a box) allure all the males round the country that are within the sphere of its attraction, and even from a great distance; who will at first fly round the box with wonderful swiftness and eagerness, and afterwards settling thereon will hunt and run about it with the greatest impatience, endeavouring to get at the inclosed female; and all this from the strongest desire of copulation; for the minute that action is performed by a male, the attractive property of the other ceases. The powers of perception and distinction, therefore, are very great; and what parts of the insects, unless it be the antennæ, are employed in this search I am at a loss to discover. However, at present, I presume it will not be necessary to offer any further reasons for using this term, as the name substituted is sufficient for it to be known by, it will fully answer the intended purpose.
The names of the other parts are too intelligible to require any explanation.
The plate annexed (being the last thing I shall speak of) requires but little to be said in its favour. The use and advantage of it is too obvious to dwell on. I have already mentioned, that engravings and delineations claim the preference in the highest degree of verbal descriptions; and as such, I presume, the reader will find this plate of the greatest service in assisting him to understand the descriptive parts with clearness and ease. I must only recommend it to him, if he is desirous of avoiding difficulty and trouble, to make himself fully acquainted with the terms and names of all the parts of insects, before he begins to read the descriptions.
