BY R. J, TILL YARD. 317 



Under this scheme the genus Synthemis falls, apparently 

 naturally enough, into the subfamily Macromiince. From all the 

 other genera in that subfamily it can be distinguished by the 

 presence of cross-veins in the basilar space. 



I have found it hard to believe that there is such a close 

 affinity between the slender, graceful, and timid Synthemis and 

 the coarsely-veined, swift and rapacious Macromia. Apart from 

 the wing-venation, Synthemis is absolutely Corduline in facies, 

 while Macromia is distinctly jEschnine. So much so that, even 

 so acute an observer as Professor Sjostedt, of Stockholm, has 

 described a female Macromia as a new j'Eschnid.'^' There are, 

 in fact, distinct Aeschnid tendencies in the whole Macromia- 

 group, and it will be interesting to see what light the study of 

 life-histories may throw on this question. I propose, however, 

 first of all, to take the whole question of the wing-venation of 

 Synthemis and Macromia, and to study it in detail. We shall 

 then see where the differences lie. 



The essential difference seems to be this. In Macromia we 

 have, in its way, as highly evolved and specialised a wing as is 

 to be found in any dragonfly. I do not mean by this that all 

 parts of the Macromian wing are as highly evolved as in other 

 groups (for instance, the hindwing-triangle is never recessed, nor 

 is the stigma braced); but that the line of development followed 

 has evolved so beautifully perfect and strong a structure for 

 flight, albeit on simpler lines than in some other groups, that it 

 may well stand as a model of perfect development. Nor do I judge 

 it alone by arbitrary standards of development, so much as by its 

 actual test in the field. The flight of Macromia is something to 

 marvel at. When collecting in North Queen.sland, I found 

 Macromia tiUyardi and Synthemis flavoterminata flying on the 

 same creek. The contrast could scarcely be greater. Of the 

 latter, specimens would often fly almost into the net, and their 

 only idea of self-preservation was now and then to rise out of 

 reach of the net, continuing their weak to-and-fro flight undis- 



* Hylaeschna paludis SjiJst. = Macromia melania Selys( ? ). 



