BY R. J. TILLYARD. 345 



Knowing that a day's collecting generally yields many more 

 males than females of any given species, I have always made 

 great efforts to secure sexual equality in my series by searching 

 out the haunts of the females. The final result appears as 

 follows : — Out of a total of 563 set specimens, 352 are males 

 and 210 females, a proportion of 5 to 3 in favour of the 

 males. This is, however, stating the case unfairly, for out 

 of several hundred unset specimens which I have collected 

 besides, nearly all are males. Taking a total of over 800 speci- 

 mens, I find that under 300 are females; so that the proportion 

 is in reality very nearly 2 to 1. Turning to species, out of 90 

 species collected, only five species are unrepresented by male speci- 

 mens; while in no less than 26 cases have I failed to secure the 

 female of a particular species at all. This is a remarkable result, 

 and appears to make it extremely doubtful whether the numerical 

 equality of the sexes really holds in the " Odonata." 



There are, however, many reasons why a collector always 

 captures many more males than females. The males are the 

 more conspicuous of the two, the more brilliantly coloured, and 

 more frequently on the wing. Moreover they love to congregate 

 in marshy spots and along the borders of creeks and rivers where 

 one is accustomed to search for dragonflies, while the females 

 often retire into the bush or hide themselves in the herbaore. 

 The female, too, is fond of coming out to feed at dusk^ when 

 crowds of gnats and mosquitoes fall an easy prey to her. I have 

 a specimen of T elephlehia GocUfroyi, a female, which flew into a 

 lighted room about 10 o'clock at night, and a female of Hemianax 

 Papioensis taken at an arc-light in the city. I do not know of 

 any case in which a male has been taken so late at night. On 

 one occasion an hour's collecting on the borders of a large lagoon 

 in Northern Queensland yielded me nearly two dozen Rhyothemis 

 graphiptera, all males; but a walk of a mile or more through the 

 bush and back yielded four females and no males. On another 

 occasion I took over a dozen Synthemis eustalacta, all males, in 

 a marsh on the Blue Mountains; on the way home two specimens 

 were captured far from any water; these were both females. 



