Surface of water.

Southland Times, Issue 19185, 24 October 1903, Page 5 (Supplement)

Surface of water.

Diagrams showing the eggs of the mosquito destroyer and a swarm of the young destroyers making for the surface in quest of mosquito larva.

sick and eventually dies. Here, then, ns it would appear, is found the most important natural enemy of the mosquito. \s such it is necessarily to be regarded as a friend to mankind, and too much cannot be done in the way of cultivating it. Dr. Stiles, it should be explained, is a helmintbologist — which menus that the study of worms is an important part of his business. He is employed by the I'lii-lie Health nnd Marine Hospital Service to look up nil sorts of animal parasites and lind out about their habit-. So it came right in his way to make the remarkable discovery here described, and to bestow the long name of Agamomermis upon the mosquito destroyer — a thread-like worm (so he describes it), half an inch long, which looks more like a bit of a horsehair than anything else, and which appears to depend upon the mosquito for a home during the larval period of its existence, though its breeding i.-i accomplished outside, in the mud of the bottom of pond or swamp. The worm, when it has attained its full development, leaves the body of the insect aud buries itself in tho soft mud at tho bottom of tbe pond or swamp, where it coils itself up into a knot together with a lot of other worms of its own kind. Several different sorts of worms belonging to the same " group " have this curious habit, from which one genus takes the name of Gordius — referring to the fabled Oordian knot. I3y-and-by the mosquito destroyer — the female, that is to say — lays its eggs, which have the form of a soft white cord. The cord breaks up into segments, and presently the tiny young ones, resembling delicate threads, are hatched. Coming out in the water, the baby worm proceeds to hunt for a mosquito

Diagrams showing young mosquito destroyers making for mosquito btrvtv in which they bury themselves, and a newly born mosquito which has been made sick in this way, and which, therefore, will die soon after birth. larva. If it is a stagnant pond or swamp, large numbers of immature mosquitoes, commonly called " wrigglers," are sure to be swimming about, and before long tho destroyer tackles one of them, entering its body nnd making itself comfortable in its abdominal cavity, Feeding upon the vital fluids of the insect, it waxes big and strong at the expense of the latter, and pretty soon the unfortunate " skeeter " begins to sicken. The malady, of course, is incurable, and after awhile' Mr. Cluex dies miserably. But it is the female mosquito that suffers worst, because the presopco of the worm in some way prevents her egg sacs from developing." Thus, even if she survives long enough to become a winged insect, she cannot lay eggs ; the race, bo far as she is concerned, comes to an abrupt end. How important this fact is, in considering the usefulness of Agamomermis as an enemy of the mosquito, must be obvious. Indeed, it is presumably on.- this account chiefly that some seasons produce so many less mosquitoes than others. When the worms happen to be exceptionally numerous they cut off the mosquito supply by destroying the breeding power of the females. The really important consideration in reference to this new and surprising discovery has to do with tho prospect of utilising the destroyer on a large scale, by artificial means, for the killing of mosquitoes. To accomplish this, it will be necessary to breed the worms and introduce them into ponds and swamps, permitting them to do the rest. It is thought that such an enterprise would not be attended with any very serious difficulties, inasmuch as tbe parasites, now that they have been identified, are readily obtained fropi the bodies qf jrifocted mosquitoes, and it bas been found easy enough to breed them. — — :.".".■■.-■■