346 NUMERICAL PREPONDERANCE OF THE MALES IN ODONATA, 



Again, a dozen males of Diplacodes melayiopsis were taken by me 

 one afternoon round a small pond near the Clarence River; in the 

 bush some hundreds of yards away I took four females and saw 

 only one male. The female of D. bipicnctata, too, was common 

 in this spot, but I succeeded in taking only one male. Still 

 another species of Diplacodes, D. hcamatodes, is abundant along 

 many small creeks and rivers; yet I never succeeded in taking the 

 female of this species until one day I returned home along the 

 railway line some distance from any water. In one of the 

 cuttings the females simply swarmed, but I saw only one male. 

 On another occasion I collected along 13 miles of railway track 

 in Northern Queensland, mostly through dense bush; out of 21 

 specimens taken, 17 were females, and two of them, which I 

 caught actually inside a tunnel, were females of a species of 

 which I have never seen the male. 



These facts, I think, prove conclusively that, except during 

 oviposition, the males and females are in many instances quite 

 separated, and only those collectors who will take the trouble to 

 search in out of the way places, often far from water, will be 

 able to obtain a good series of females. That this separation 

 and retirement of the females is the reason for the apparent 

 numerical superiority of the males, there can be very little doubt. 



But something more than this is required to prove the actual 

 numerical equality of the sexes. Even when searching for the 

 females in their special haunts, it is only on very few occasions 

 that they will be found in anything like the abundance of the 

 males in their special haunts. A glance at the cases of R. 

 graphiptera and D. melanopsis given above (and many other 

 instances could be given) still leaves us with the conviction that 

 the males are greatly in the majority. To prove that either this 

 or the contrary is really the case, it would be necessary to show 

 the proportion that actually exists among the nymphs of any 

 given species. This I have endeavoured to do by rearing a large 

 number of the nymphs of any given species. The nj'mph 

 that is most easily obtained around Sydney is that of 

 Lestes Leda, one of our commonest Agrionids, and one 



