Many species of the genus Silba Macquart (= Carpolonchaea Bezzi) are important pests of fruits and vegetables during their larval stages but taxonomically the adults are poorly known. Representatives of 15 species of the genus from widely separated localities in the Old World have come to hand during studies on the family. This paper clarifies the identities of the males of these 15 species, six being described as new to science.

Sex anomalies have been used in an attempt to homologize the male and female genitalia of insects. Studies of some sex anomalies (Michener, C. D., Ann. Ent. Soc. Am. 37: 336-351.1944) suggest that the second valvifers are homologous with the gonocoxites (phallobase); the second valvulae probably are homologous with the penis valves; and the third valvulae are homologous with the gonostyli (parameres). Homologues of the first valvifers and first valvulae of the female are absent in the males of Pterygota.

Recent studies of the genus Culicoides have exposed many new species and presented taxonomists with a difficult problem in using accepted characters or obtaining new differentiating characters clear-cut enough to provide suitable separation.

One such new character is the tibial comb, a structure found on the distal tip of the hind tibia of both sexes of ceratopogonid midges. Fox (1952) illustrated the tibial comb of several Puerto Rican Culicoides and (in litt.) suggested that this character might prove useful in separating other species of this genus. The present study appears to bear out this suggestion. Moreover the study indicates that the character might prove useful in other genera as well.

In a recent paper Taylor (1955) has discussed the status of biological control with particular reference to its present and future value as a method of control of insect pests. A number of his remarks are questionable, and his conclusions that present methods of biological control are of little value are not valid. His broad thesis is that insect pests with which the biological control method is effective have already been satisfactorily dealt with and that there no longer remain problems where spectacular results may be expected: moreover, that with the modern insecticides available, biological control has in many cases been rendered useless. It would be as well therefore to examine carefully his main contentions, and it should be pointed out at the outset that Taylor's criticisms of the methods of biological control, and of the claims made by entomologists working in this field, are vague, and although he does not actually say so he insinuates that biological control workers make or have made unjustified claims as to the success of a number of projects undertaken.