_THE AUSTRALIAN NATURALIST. 107 
und refill the space beneath the wing covers with fresh air. 
The larvae are as voracious as the adults, and armed with 
large hollow jaws suck the juices of their prey. They breathe 
through spiracles at the tip of the abdomen, and not by 
means of gills as do the larvae of the Whirligig Beetles (Gyri- 
nidae). These Whirligig Beetles all will remember by their 
wild, eccentric skating on the surface of pools. 
Probably our largest water beetle is Hydrophilus lats- 
palpus, over an inch long, and glossy black. It is so: slug- 
gish in the water that after seeing the swift darting Dytisci- 
dae and the Whirligigs, it gives one the impression it is a 
land beetle which hag fallen into the water. It uses its legs 
alternately, not in pairs, as the other water beetles do. I 
have seen a specimen swimming in the salt water of upper 
Middle Harbour, but it was probably there by accident. 
In America and Europe a few Chrysomelid beetles of 
the genus Donacia lay their eggs on water weeds. The larvae 
drop to the bottom and feed on the weed stems, using a 
special spine with which they are provided, for puncturing 
the pith cells and obtaining a supply of air for the spiracles. 
which are at the base of the spine. These are instances of 
air breathing, leaf-eating beetles acquiring aquatic habits in 
the larval stages. 
Coming to the Dragon-flies (Odonata), we find them 
plentiful in Australia, and Mr. Tillyard has contributed valu- 
able papers to the Proc. of the Linnean Soc. of N.S.W. 
on the habits of some of our species. Dragon-flies are often 
called Horge Stingers, though perfectly harmless and not 
possessed of a sting. Their wonderful flight and brilliant 
metallic tints are known to all, but in their young stages in 
water they present dirty brown or greenish colours, and crawl 
upon the mud and weeds. Bothi young and adults are pre- 
daceous. When skimming over the surface of the water as 
adults they are not merely enjoying the glorious sensation of 
flying, but engaged in a deadly attack on midges, mosquitoes, 
moths, etc., which may be in the air. The jaws are broad 
and embracive, and with mouth wide open they rush through 
the air seizing and devouring their small prey. The eggs 
of some are dropped indiscriminately into the water. Others 
—for instance, the common Lestes /eda, the slender blue- 
banded Dragon-fly of Sydney—lay their eggs in water weeds. 
I recorded for the first time the egg-laying habits of the 
above species in this journal in 1907. The female, either 
alone or accompanied by the male clinging to her neck, de- 
scends the weed, sowing her tiny white cylindrical eggs into 
the weed by means of her needle-like ovipositor. The curious 
point is the female, perhaps with male, descends under the 
water, still laying her eggs in the weeds, and they may re- 
main 10 minutes below water. Air is observable as a film 
