His Classing of the ~Caterpillars~ will be found of great Use; for if it be enquired what ~Fly~ any ~Caterpillar~ that may happen to present itself will produce, by observing its Character you will easily be satisfied (if it is in this Collection) and be likewise taught what its proper Food is, &c. ~Names~ are absolutely necessary to distinguish one ~Fly~ from another, and enable the Curious in this Study to communicate any Observations they may make; which, without giving Names to the ~Flies~, would be very difficult, if even possible to be done; as they must be greatly at a Loss to make others perfectly understand what ~Flies~ they are treating of. The worthy Members of the AURELIAN SOCIETY, and several other ingenious Gentlemen, have been so sensible of this, that they, from Time to Time, have thought proper to bestow some Name on every Species that has come within their Knowledge._ _Indeed Names are arbitrary, and if remembered, and the Intent of them well understood, may, whatever they are, serve the Purpose of giving them: But here, as in every Thing else, a Propriety is to be aimed at, and the Names given ought to denote some distinguishing Particularity, and that the most obvious, in the Subject on which they are bestowed, so as to make the Name, if possible, descriptive of the Thing: Which Rule has been followed as strictly as might be in naming the ~Moths~ and ~Butterflies~ contained in this Work: that is to say, the Shape, the Colour, the Marking, the Food, or the Place where found is what they are named from. But in doing this, where the Author found them named to his Hands in this descriptive Manner, he has gladly retained the Name they had already, and only presumes to bestow Names himself on such as either had none at all, or which he thought not sufficiently denotative of the particular Flies intended to be known by them. The Division of the Work into Books and Chapters may need some Explanation, since under some of the Divisions very few, or even but one single ~Fly~ is placed; the Reason whereof is, that the Plan here laid down is intended for the Arranging of all the ~Moths~ and ~Butterflies~, whose Progression is known at present, or shall hereafter be discovered in ~England~; of which, as the ~Flies~ here given are but a small Part, this must be considered but as an Out-line to be filled up occasionally. It is hoped the Directions here given how to collect the ~Caterpillars~ or ~Chrysalides~, how to feed and take Care of them, how to preserve the ~Flies~ when bred, and where and at what Times they may be found most easily, will prove both acceptable and useful to every curious Collector; and as the Author thinks himself under great Obligations to the Subscribers to, and Encouragers of this Undertaking, a List of their Names is added as a Memorial of his Gratitude. These Things being premised, we come now to give a short Sketch of the Natural History of the ~English Moths~ and ~Butterflies~ in general._