BY R. J. TILLYARD. 273 



question be answered affirmatively, we can indicate with any 

 certainty which portions of that knowledge are essential, and 

 which are not. 



Now there will be, in any group of Orders, some which show 

 definite specialisation above the others: as, for instance, the 

 Lepidoptera and Diptera above the Trichoptera and Mecoptera. 

 All entomologists are agreed upon this. Is it more necessary to 

 attain to the specialised knowledge of the lower groups, or of the 

 higher groups ? It will be seen that Meyrick was a specialist in 

 the higher of the two Orders which he discussed, while the 

 same is true of Handlirsch, in a more general way, since he, 

 everywhere, shows a far more intimate knowledge of the Lepi- 

 doptera and Diptera, but especially of the latter, than he does 

 of the Trichoptera and Mecoptera. Would it not be preferable 

 for the author, who is to attempt a satisfactory solution of this 

 problem, to throw the main weight of his studies on to the side 

 of the more archaic Orders, which, unfortunately for the progress 

 of Entomology, have been so neglected for many years, and to 

 be content to attain to a first-hand knowledge of only the more 

 archaic types within the more highly specialised Orders? 



I believe that this question must be answered in the affirma- 

 tive, for some very good reasons. Firstly, the knowledge of the 

 more archaic Orders is the only sure foundation upon which the 

 Phylogeny of the higher Orders can be built. Any attempt 

 without this knowledge is merely building up a house without 

 la3'ing secure foundations. Secondly, the connections sought for 

 in the tracking out of the ancestry- of the higher Orders must be 

 those between some members (either existing or extinct) of the 

 more archaic Orders and the least specialised families of the 

 higher Orders. Thirdly, if at any time the problem transcends 

 the attainable bounds of knowledge of the investigator who has 

 adopted the course here advocated, he can always call in the 

 advice of "the specialist, who possesses just that very type of 

 knowledge, in his own group, which would render the Phylo- 

 genist's task too overwhelming for him, on the principle of "not 

 being able to see the wood for the trees.'' And, finally, there 

 are already, in Entomology, specialists enough in all the higher 



