274 THE PANORPOID COMPLEX (Introduction), 



Orders; so that the chance of being brought to a full-stop, 

 because nobody in the world can supply the gap required, is so 

 unlikely a possibility that it may be dismissed without further 

 thought. 



That being so, T decided that the investigation into the Phylo- 

 geny of the Panorpoid Complex was a task that I might venture 

 to undertake, and that its difficulty and immensity would be 

 more than compensated for b\' the advantage to Entomology in 

 general, if a satisfactory solution could be found. Having, then, 

 decided to confine mvself to researches within the limits indi- 

 cated in the previous paragraph, I have carried out an exhaustive 

 surve}" of the older Orders under review, viz., the Planipennia, 

 Megaloptera, Mecopteia, and Trichoptera, and have been content 

 to study, in the immense Orders Diptera and Lepidoptera, mainly 

 the older families only. The survey has been extended far 

 enough to give me some idea of the position and inter-relation- 

 ships of all the important families of each of these Orders; but 

 intensive study has l)een chiefly confined to the older families, 

 together with other more specialised types in which I thought I 

 could recognise characters of value as evidence on the question 

 at issue. Further, it will be at once evident that the equipment 

 of the author who attempts to solve this immense problem will 

 not be complete unless he masters what there is to know about 

 the Fossil Record of the Orders in question, and of their possible 

 ancestral Orders. This also I have endeavoured to do. The 

 fortunate circumstance of my having in my hands a large amount 

 of new and unique material of this kind from the Permian and 

 Triassic strata of Eastern Australia has been one of the chief 

 factors in my decision to undertake this task; indeed, it has 

 almost imposed the obligation upon me, since nobody who has 

 not studied these fossils could possibly be so favourably placed 

 for discussing this question as I happen to be, simply through 

 this great good fortune. 



It will, I think, be readily granted that the Order is the only 

 satisfactory unit upon which a study of this kind can be based. 

 We have, therefore, to consider what view of an Order we must 

 take, in dealing with it as a separate unit in a paper such as 

 this. 



