4(> NOTES ON A MALAKIA-CAKRYING MOSQUITO 



are fournl around ]>risbane, but in small numbers. Out of a 

 thousand collected under ordinary circumstances, probably only 

 one would belong to this particular variety. As you travel 

 north I think the proportion increases. Some came to me from 

 Cairns, and the batch contained twenty per cent, of the 

 Anopheles. It must be understood that the Anopheles are naturally 

 free from malarial germs. It is only where they can suck the 

 blood of malarial patients and so receive the germs that they 

 become propagators of the disease. The eggs are difficult to 

 find. They are too small to be seen by the naked eye, being 

 only the tiftieth of an inch in length and two hundredth in 

 breadth. They aie not massed together into a raft like the 

 ordinary culex eggs, but are laid separately on the water. In 

 Fig. 1 a number are seen. They are shapen like a beautiful 

 little boat with curved ends. The boat used by the ancient 

 Britons called a coracle bears a strong resemblance to them. 

 On looking at the upper edge, or gunwale, a slender line is 

 traceable. This consists of a thin loose membrane falling over 

 the inside of the vessel in transverse folds. Turning a boat 

 bottom up this silken canopy may be seen projecting on both 

 sides. This no doubt helps the boat to preserve an even keel, 

 and probably acts as an attachment to anchor it to a twig or 

 stone, and when the egg is hatched its thin skin can easily be 

 ruptured by the young larva in its effort to crawl into the water. 

 In the next stage the larva are easily distinguished by 

 certain peculiarities of structure and habit. They can be found 

 in our district at all times of the year in suitable places. The 

 most likely ai'e low-lying grass fields, which are often submerged 

 and form shallow pools not sufHciently deep or permanent for 

 the existence of tish. I have never but once found the larva 

 separate from those of the ordinary mosquito. In Queensland 

 the two varieties are generally together, and I have found them 

 so at Southport and the Tweed Heads in old barrels containing 

 water in the open air. The most distinguishing feature is that 

 while the culex larva hang with the tip of the tail above the 

 water, and the body hanging down in an almost perpendicular 

 direction, the Anopheles stretches himself out on the surface 

 like a bit of stick. It may be vanity that induces him to assume 

 this position, for he is certainly more handsome than the 

 common variety. The body is usually of a mottled brown 

 colour, occasionally they are black, with a white collar and one 

 white abdominal segment. On the back of the thorax is often 

 seen a shield, in shape like a diamond, a heart, or the letter U. 



