The generosity of the Commonwealth Fund enabled the writer to spend the years 1933 and 1934 at the Riverside Research Station of the University of California, U.S.A. While at this station he gave most of his time to the study of beneficial insects, particularly the parasites of Pseudococcus maritimus Ehrh. He was thus placed in a position to benefit from the experience and kindly co-operation of the well-known authority on biological control, Prof. Harry S. Smith, and his able staff.
The Ceratitis (s.l.) group of the Trypetidae with which the genus Pterandrus Bez.* is associated, is divided into various genera or what may perhaps be little more than subgenera. They are based mainly on certain male secondary sexual characters. Females may, however, to some extent be located in their correct genera on general appearance (brown colour, wing-pattern, etc.) but the inclusion of smaller, darker species in Pterandrus; gives rise to an unsatisfactory position.
Dira* jansei Swierstra. Plate 1. Egg. The eggs are scattered in the grass. They are very pale watery yellow when laid and do not darken much until the larva takes shape inside (Fig. 2). They are 1 mm. in diameter, by 1.1 mm. high with a very fine tracery, only visible under high magnification. The larva emerges after 12 days.