BY R. J. TILLYARL 419 



I have already discussed* the connection of Jlesperocordulin 

 with the EucorduUna, and have given reasons why it should 

 be included in that group. We see, therefore, how it forms 

 the connecting link between them and (Jorduleyhya. 



Reviewing the above evidence in toto, I conclude, (i.) that 

 a Eucordidian connection for Cordulephya is proved; (ii.) 

 that its apparently Idocordiduui relationship in wing-vena- 

 tion is due to convergence by reduction : (iii.) that the Eucor- 

 ditlian connection is strong enough to justify us in including 

 it in that group, rather than placing it in a separate group 

 of its own. 



Note A. — On the Reduction-Process exhibited by Cor- 

 dulephya. —The important part played by csenogenetic reduc- 

 tion in the formation of oiir present-day Odonata has been 

 hitherto ignored, though there can be no doubt that it has 

 played a far more effective part than any other form of 

 specialisation. The result of ignoring it has been that a 

 highly erroneous view of the phylogeny of the families of the 

 Odonata is growing up. When their life-histories come to be 

 written, I venture to state that such forms as many of the 

 Protonetira (including Selysioneura, claimed by Foerster to 

 be one of the most promitive of Odonate types), Hemiphlebia, 

 Nanno-phya, Agrionoptei-a , and many others in which reduc- 

 tion can be traced, will be found to bo highly specialised by 

 reduction, and not truly archaic by comparison with other 

 existing forms. W^e are so especially apt to think of Aus- 

 tralia as the home of archaic forms, that we forget that 

 Europe and Asia possess forms equally archaic. [Cordule- 

 gaster and Paheophlehia are probably as old as any now 

 existing). We must not argue by analogy from the distri- 

 bution of the higher animals, for the Odonata are a very 

 ancient order, and reached a high degree of development long 

 before Australia was as isolated as it now is. Nor have the 



* Loc. cit., p. 381. 

 36 



