Aëdes argenteus, Poiret, is a very variable mosquito, and it was thought that it would be interesting to examine a number of freshly-hatched and therefore undamaged specimens and to note how many conformed to the original description. No difficulty was experienced in obtaining the necessary material, as collections of larvae are received daily from the Medical Officer of Health. One thousand of each sex of the species were mounted in the order of their emergence from the pupal case and were examined under the binocular microscope. The one constant feature was found to be the lyre-shaped marking on the thorax, although even here the outline and the centre lines varied in breadth and in colour, and the centre lines varied in length. But as the abdomen and the hind tarsus showed the greatest variations, the present paper is restricted to a description of these.