Study Of Mosquitoes

Interesting Results Gained by Photographing the Insects.

WORK OF A BOSTON SCIENTIST.

William Lyman Underwood Has Made Negatives of the Pest In All Stages of Development-Difference Between Larvae of the Anopheles and Culex Species Clearly Shown.

An interesting series of photographs of mosquitoes has been made during the last winter by Mr. William Lyman Underwood of the Massachusetts Institute of Technology in Boston.

Mr. Underwood's pictures include both the "anopheles" and "culex" varieties. The anopheles mosquito, as scientists have recently discovered, is the one which carries the germ of malaria. The culex is harmless, but is quite as annoying and even commoner, and both are comprehended indiscriminately in the warfare which sanitarians are preparing to wage during this spring and summer upon the breeding places of this sometimes dangerous pest.

Mr. Underwood has for some time been interested in photographing wild animals from life, and there is a humorous touch in the fact that his present subjects have occupied a cage originally built to contain a wildcat. The iron bars were covered with gauze, and a small aquarium was placed in one corner containing water plants and a little marsh slime so as to afford the female mosquito an opportunity to lay her eggs under natural conditions. The insects could probably have lived for some time on the water and the aquatic plants which were thus supplied them, but to make sure that they should be thoroughly well fed, slices of banana were given them every few days, a delicacy which they apparently appreciated highly. By this means both varieties-the malarial and the nonmalaria-were raised from the egg to the fully grown winged insect.

Mr. Underwood's photographs bring out the difference between the larvae, or "wrigglers," of the two species very clearly. The anopheles larvae usually stay on the surface of the water, where they are hatched out from floating masses of eggs and eat and breathe, their two principal functions, in a horizontal position, seldom going to the bottom unless alarmed. The culex larvae, on the other hand, ordinarily live at the bottom, coming to the surface only occasionally to breathe, where they hang head down at an angle of about 45 degrees while they take in air through the long breathing tube which they push up through the surface film of the pool.

Almost every one has heard of the use of kerosene oil spread on the surface of stagnant water as a means of destroying mosquito life. Of particular interest, therefore, are certain photographs which Mr. Underwood has taken showing exactly how kerosene affects the larvae when they come to the surface and thrust their breathing tubes into oil instead of air. The contortions by which the wrigglers attempt to get rid of the oil are sometimes quite astonishing, but never successful. Other photographs are hardly less interesting. For instance, the newly fledged mosquito has been photographed by flashlight just as it is drawing its body from the shell, or pupa. The larva is shown changing into the pupal state, and adult mosquitoes are compared in many characteristic attitudes and from many points of view. It is believed that the collection is the first attempt of the kind on anywhere near so large a scale to record this unique phase of insect life.