'Sphinx Vespiformis,' published some time since, that seven was the predominant number; and that, in every group of seven, whether the group be large or small, one of the seven is central, and the other six surround it, and are each connected with it. As a specimen of this arrangement the following location of the seven classes may suffice.

This septenary system is now making evident progress, after having been written against with what the author thinks unnecessary severity; unnecessary, because temperate argument and persevering enquiry do more to elicit truth, and fair, moderate statements more to establish it, than angry words and flat contradictions. The author has never met with a single argument, either in print or in the course of conversation, to shake his steadfast belief that the septenary system is the system of nature. Almost every new form of insects that we receive from distant countries,almost every newly ascertained fact in metamorphosis, adds an additional link to the evidence already recorded on this interesting subject; whereas, were the system ideal or applicable only to the comparatively small number of insects with which we are acquainted, each new form must prove an argument against its truth, and consequently a barrier to its reception.

They who have only superficially glanced at this system find a ready argument against it in the obvious difficulty of resolving all groups into any uniform number of divisions, and thus they set a stumbling-block at the very threshold of the enquiry. The preponderance of the number seven is apparently the effect of the centrality of types, precisely as the hexagonal cells of a bee-hive result from the pressing together of circles. But neither in the centrality of types, nor in the mystic number seven, is the test of the septenary system. Systematists have always insisted on some one or two characters which they conceived to be of greater value than certain other characters: thus Swammerdam believed that in the preparatory states of an insect was to be found the clew to its natural situation: Linneus, whose name is familiar to every child who has ever sought out the name of an animal or plant, believed that difference in the structure of the wings afforded the best divisional characters and lastly, Fabricius, discarding the ideas of Swammerdam and Linneus, insisted that in the variations of the mouth was to be found the key to natural arrangement. Thus we have three systems; that of Swammerdam, or the "metamorphotic," that of Linneus, or the "alary," and that of Fabricius, or the "maxillary." All naturalists have acknowledged the merits of one or other of these systems, and the numbers in favour of each may be said to be nearly balanced. Latreille, the great master of modern Entomology, not knowing to which of the three to give the preference, proposed a fourth, in which he attempted to combine the other three; but in this he failed, owing to his adherence to the belief that no arrangement otherwise than in a right line could be in accordance with the plan of nature: Latreille's system was called the "eclectic."

Now although the metamorphotic, alary and maxillary systems are so carried out as to be at variance with each

other, and although the various advocates of each have in set terms denounced the others; yet the septenary system is in perfect and exact accordance with each of them and depends on them as the best tests whereby its truth may be made manifest: for whether we avail ourselves of the approved characters of metamorphosis, wings and mouth, or draw up fresh characters from other prominent parts yet untested, as the pro- meso- and metathorax, we shall find the variations of each and all perfectly in accordance with the septenary system: no arrangement dependent on metamorphotic or structural variation can ever interfere with it.

The position of Lepidoptera at the head of this system is merely for the sake of convenience; the relative position of the classes must be preserved, but they are supposed to constitute a circle, no one point of the circumference of which is superior to the rest.

Besides these seven classes others under the name of orders have been made out for the reception of single genera, as Sirex, Aphis, Forficula, Sialis, Coccus &c., and the larger classes have occasionally been divided, without any other apparent object than that of imposing new names. The leading entomological writers of all ages, Aristotle, Linneus, Fabricius, Latreille, Straus-Durckheim, Burmeister, &c., &c., have preferred adhering as nearly as possible to the most simple and obvious primary division of insects. The last-named of these authors observes, "The subdivision of insects into many orders, which the English are especially fond of, certainly merits no recognition; only where nature has set true limits let them be divided, and let us not wilfully destroy the beautiful picture of harmony she every where presents us with." The scientific world seems to agree with this dictum, for the new names of orders are very rarely transplanted from the pages in which they originally saw the light.

The name of 'Sphinx Vespiformis' has little connection with the subject of the essay further than its being the original name of the insect selected as an object whose place in a natural system the author proposed to find. Concerning the insect to which the name was strictly applicable some doubts appeared to exist, and the author attempted to show that it was synonymous with the Ægeria Asiliformis of our cabinets. The insect is figured below.

The Spurge Hawk-moth sucking the blossom of Honey-suckle.

CHAPTER II.

OF THE CLASSIFICATION OF LEPIDOPTERA.

CHARACTER amorphous : i. e. larva and pupa bearing no resemblance in external appearance to the imago: pupa perfectly quiescent, having the limbs and parts of the mouth enclosed with the body, in a hard brittle skin or case. Larva with strong corneous mandibles, moving

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