1. The larva of the clothes moth Tineola bisselliella Hum. grows well on an artificial diet consisting of casein, glucose, yeast, cholesterol, salt mixture and water. The presence of glucose is unnecessary, and that of cholesterol and yeast necessary for growth.
2. Yeast has been successfully replaced by a mixture of eight pure vitamins of the vitamin B complex. In the absence of either riboflavin, choline chloride, pyridoxin or thiamin growth is retarded, while little or no growth takes place in the absence of pantothenic acid or nicotinic acid. Inositol and p-amino-benzoic acid do not seem to be necessary, and the value of biotin for growth is doubtful.
3. The presence of a fat in the diet is of no or very slight value.
4. Like many other insects, the clothes moth grows faster on flour of high than of low extraction, but even wholemeal flour is far from being an optimal diet.
5. Growth is faster at 70% relative humidity than at 50 and 30%, but even at 30% most larvae complete development.
6. These findings are discussed in connexion with the natural occurrence of clothes moth larvae on woollen cloth, flour and other dried foods.