Tune, I92I.1 CraMPTOX: EvOLUTIOX OF THE AXTHROPODA. 91 



I suspect that Haiullirsch's overweening^ desire to derive winged 

 insects directly from trilobites is tlie cause of his attempt to deny 

 to Machilh. Lcf^isma and related Apicrygoia their rightful positions 

 as the nearest known representatives of the precursors of winged 

 insects, and to relegate them to the subordinate position of mere 

 '■ degenerate " winged insects, for there is a wide gap between these 

 Apterygota and the trilobites and they do not seem to approach the 

 trilobitan type any more closely than the winged insects themselves 

 do — and if winged insects are to be derived directly from trilobites. 

 their precursors must perforce resemble trilobites more closely than 

 winged insects do! Therefore, in order to maintain his unfounded 

 theory that winged insects are descended directly from trilobites. it 

 was necessary for Handlirsch to sweep the true ancestral types of 

 insects aside as degenerate winged insects, since they do not fit into 

 his preconceived scheme of the origin of pterygotan insects. As an 

 anatomist, however. I cannot avoid the conclusion that such Aptery- 

 gota as Macliilis. Lcpisiiia, Xicolctla. Caiiipodca, etc.. are far more 

 primitive than winged insects (as is also shown by the embryological 

 development of these forms) and if the facts of the case do not fit 

 into one's theory, it is much better to discard the theory and stick to 

 the facts I 



I have i)erhaps laid greater emphasis upon Handlirsch's views as 

 to the origin of winged insects, than should be given to a theory 

 which was evidently developed merely as a side issue of his monu- 

 mental work on fossil insects ; but so many recent writers, who have 

 not taken the trouble to go into the matter at all deeply, have set 

 forth this unfounded view of Handlirsch's (even in text-books) as 

 though it were absolutely demonstrated, that it is high time that some- 

 one should call attention to the many obstacles in the way of accept- 

 ing such a view. There are many other insuperable obstacles to the 

 accei>tance of the view that winged insects (or even the most primi- 

 tive of the apterygotan types which preceded winged insects) may be 

 derived directly from trilobites; but since this paper deals with the 

 mandibles alone, I shall confine myself to the evidence offered by 

 these structures — which is quite sufficient in itself to disprove Hand- 

 lirsch's theory, since the mandibles clearly indicate that there must 

 have been a great number of intermediate stages between so primitive 



