728 THE DRAGONFLIES OF SOUTH-WESTERX AUSTRALIA, 



of 8 ending in a black hook, sharply upcurved. Ajypendages 

 short, 0-7 mm., straight, black; separated by a projecting tubercle 

 on 10, black and hairy and as long as the appendages; below this 

 is a second tubercle, rounded, hairy, dark brown. 



Hah. — Running streams and mountain-brooks all over the 

 S.-W. district. A few specimens seen on Mungar's Lake, Perth. 

 Abundant at Margaret River and Bridgetown. 



The females are very rare, and, as in the preceding species, the 

 males outnumber them by 20 to 1. In both cases this is 

 probably accounted for by their being seldom on the wing, and 

 retiring into the thick bush. The few females I have taken have 

 been generall)^ very immature, and we may perhaps see in this a 

 wise provision by Nature for the preservation of the species. 

 If the females only mature slowly, they are enabled to outlast 

 the dry months at the end of summer, when many of the 

 streams in which they breed have ceased to run, and they 

 probably only deposit their ova late in the autumn, when the 

 rains have commenced. There would always be plenty of males 

 left over, even though they mature earlier, to provide for the 

 fertilisation of the ova. This is borne out indirectly by the fact 

 that, in the case of the three Synthemids which occur in S.-W. 

 Australia, I never once took a pair in cop., even at the end of 

 Januar}^, though all other species were frequently found so. 



This exceedingly graceful insect has an easy flight, going to 

 and fro in small clearings near the brooks, or up and down some 

 small and shady reach. They never go far from water, and are 

 very easy to capture. On hot summer days they sometimes hawk 

 about swiftly over the streams, but it is the exception to see 

 them flying at all fast. 



Family .ESCHNID.E. 



Subfamily GOMPHIN^. 



14. AusTROGOMPHus coLLARis Selys. 



Common on most of the mountain rivers and brooks. Also 

 recorded from South Australia and Victoria. It is fond of 

 sitting about on trees and bushes overhanging the water, or on 



