268 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.xxxiii. 



sive correspondence has been carried on with Doctor Calvert, Professor 

 Needham, and Mr. Rolla P. Ciirrie, to all of whom I am indebted for 

 9,dvice and suggestions. I have tried to harmonize these suggestions 

 as nuich as possible, and the names used in explaining the diagram 

 of wing-venation are the result. 



In the paper on the subfamily Calopterygin^ the species discussed 

 were mostly well known and represented by large series of specimens in 

 many collections, but in the subfamilies at present under discussion 

 an entirely different condition exists. The reasons for this may be 

 briefly discussed. 



In the Calopteryginae there are species in wliicli the differences in 

 color between the sexes are probably as great as in any species of bird 

 or butterfly, although those peculiar secondary sexual characters of 

 the male usually shown by such birds and butterflies are wanting in 

 the order Odonata." Of the oriental genera of Calopterygina? Bliino- 

 cypJia is the largest, and shows a maximum development in these 

 color differences. The Calopteryginse are not specialized for pro- 

 tracted flight, but spend nuich of their lives near their birthplace; 

 or if they wander it is by successive flights in an environment gen- 

 erally similar to their accustomed daily haunts. Nevertheless their 

 flight may be swift and mobile. Like the highl}^ colored humming- 

 birds, some of them at least are pugnacious, though evidences of 

 injuries to each other from this cause are wanting. Two males of 

 Calopteryx angustipennis will perform such rapid evolutions about each 

 other that the eye can scarcely follow them. Males of Hetserina wage 

 similar warfare. It would be strange if males of RhinocypJia did not 

 fight ill the same way. In Bhinocypha the hyaline spots in the wings 

 of certain males might well serve the same function attributed to 

 ej^e-spots and other striking markings on the outer portions of the 

 wings of Lepidoptera,'' but none of the many specimens I have seen 

 was so damaged as to indicate that they do so serve. In fact, I 

 know of no evidence that the brightly colored and often metallic 

 Calopteryginse are ever devoured by birds. The display of colors by 

 the male before the female has been recorded for two species belong- 

 ing to two widely different genera, though the possibility of voluntary 

 sexual selection by these insects is, it appears to me, very remote. 

 Those most active in their display, however, probably would be the 

 most vigorous and liighly colored of their associates and would, in 

 competition with others of the same species, stand the best chance of 

 reproducing. The male abdominal appendages in this subfamily are 

 but little specialized, and throughout the group are remarkably 



a Some stigmatic differences may offer an exception to the rule. 



& These markings are supposed to produce on the insects' natural enemies the false 

 impression that thoy are real vital organs, by which they may be captured with 

 certainty. 



