BY R. J. TILLYAPr). 271 



sent the oldest type, within the Order. Having then discovered, 

 in the living genus RhyacopJula of the Order Trichoptera, a 

 venation with apparently all the essential characters of the 

 Jugatse, he claims that the Jugatie, and therefore all the Lepi- 

 doptera, are to be regarded as having had a Rhyacophilous 

 ancestor. 



If the characters considered by Meyrick were the only ones 

 that concerned the question, and if the Orders Trichoptera and 

 Lepidoptera were so isolated from all the other Orders of Insects 

 that there could be no question of affinities in any other direc- 

 tion, Meyrick's solution might be accepted as correct, in spite o' 

 its having been based mainly upon the wing-venation only. But 

 this is not the case. As we shall see, the Order Mecoptera has 

 quite equal, if not superior, claims to be regarded as the ancestral 

 type from which the Lepidoptera sprang, while the claims of the 

 Planipennia, in certain directions, may by no means be over- 

 looked. Moreover, no attempt was made to test the claim, which 

 surely can legitimately )je made, that the Trichoptera themselves 

 are a by no means unspecialised Order, with almost as much 

 right to being considered an end-term in a Phylogenetic Series 

 as the Lepidoptera themselves. 



Many of these objections to the method of procedure adopted 

 by Meyrick are overcome by the method which Handlirsch fol- 

 lowed. This author, first of all, considers the relationships of 

 the Trichoptera with the Mecoptera, and concludes that the 

 former are an offshoot of the latter. He then propounds the 

 question as to whether the Lepidoptera are to be legitimately 

 regarded as the derivatives of the Trichoptera themselves, or 

 whether we are compelled to go further back, to the older 

 Mecoptera, in order to indicate their ancestors. His review of 

 this question is, in its way, a masterly exposition of the facts, as 

 far as he knew them; and his conclusion, that the Lepidoptera 

 are not descended from the Trichoptera, but directly from tlie 

 older Mecoptera, cannot fail to commend itself to all biologists, 

 if the facts that he quotes are really correct. 



Here, then, comes in the question which I have already men- 

 tioned, viz., the amount of equipment of specialised knowledge 



