Fruit-piercing Lepidoptera constitute an important problem in some parts of the world, such as Africa, Australia and India; they also occur in Ceylon, Fiji, Dutch East Indies, Indo-China, Japan, Malaya, Samoa, and South America.In Sierra Leone, grape-fruit, orange (sweet), mandarine, tangerine and sweet lime, are affected in addition to cashew, mango, bread-fruit and jak-fruit; whilst in other countries apple, apricot, banana, fig, grape, guava, litchi, nectarine, peach, pear and pomegranate, have been recorded as other adult food-plants; it is noteworthy that in South Africa grape-fruit does not appear to be attacked. Available information regarding fruit-piercing species and their biology is meagre compared with that of many other groups of economic insects, and it is considered desirable to place on record observations made in Sierra Leone.Difficulties in the way of the study of these insects are the lack of knowledge regarding (a) larval food-plants; (b) characters and habits of the larvae; (c) the breeding areas and possible migratory habits of the larvae; (d) the breeding areas and possible migratory habits of the adults of some species.Unless otherwise stated this account applies to Njala, where there is a plot of budded citrus; the trees were planted in 1925-1927 and mainly consist of Late Valentia and Washington Navel orange, and Marsh and Foster grape-fruit. The sweet lime, mandarine and tangerine are about ten years older.