49 



Mr. MacLeay, who, it will be remembered, discovered that one 

 of each of his five groups contained types of the other four, besides 

 a type peculiar to itself. This quality must hold good in any 

 group thus selected for a centre ; it must contain types of the six 

 surrounding groups in the first place. Now, is this applicable to 

 Papilio ? Have we not already experienced the greatest difficulty 

 in finding three good approaches, the smallest number which a 

 siib-class can possess ? How then can we hope, by any good 

 fortune in discovery, to make ourselves masters of three other 

 entirely new ones, and these to sub-classes to which it is con- 

 fessedly the most unlike ? Phalsena, on the contrary, presents us 

 with Lasiocampa, ^geria, Cilix, Lithosia, Apatela and Orgyia, 

 five of which genera beautifully typify the approximating sub- 

 classes. The preference on this score then is decidedly with 

 Phalsena. 



The second position, that it should contain a type peculiar to 

 itself, is almost a matter of course ; but my own idea is, that the 

 very centre should not only be a type of the genus, or order, or 

 sub-class, but of the class itself of which it is the centre. From 

 this position, then, a further and still more important question 

 arises, — What is the type of Lepidoptera ? The parts which 

 afford the generic characters of Lepidoptera, and, I believe, 

 generic characters in the perfect state are the only ones of any 

 value, are these — the mouth, palpi, antennae and wings ; and, as 

 no medium can constitute a type, the excess of these characters, 

 whether superlatively or diminutively considered, must be resorted 

 to as the most probable means we possess of discovering what 

 this type may really be. First, then, the mouth. In Lepidoptera, 

 we find two distinct characters in this ; — first, its entire absence ; 

 secondly, its being furnished with prodigiously long antlia. The 

 first character is that of Phalaena, the second that of Sphinx. 

 Next, the palpi are either entirely obsolete or exceedingly pro- 

 minent, the first in Phalasna, the second in Pyralis. Thirdly, 

 the antennas are remarkably pectinated, or clavated, or setaceous : 

 the first character is that of Phalaena, the second that of Papilio, 

 the third that of Noctua. Fourthly, the wings are enormously 

 expansive in proportion to the body, or remarkably small, — the 

 first is the character of Phalsena, the second that of Sphinx. 



