The Procaviidae (hyraxes, dassies or rock-rabbits) have persisted with very little modification since the Upper Eocene period. This same conservatism has caused the modern members of the group to be exceedingly hard to classify satisfactorily, so that few mammalogists are agreed as to the number of genera which should be recognised. But Bedford (1932), who was the first author to make a systematic study of the lice of the South African hyraxes, made an interesting and significant discovery, namely, that certain of these lice are apparently more specific in their choice of host than are any other known lice, occurring each on one of the forms attributed to Procavia capensis or Heterohyrax syriacus and not on other forms of these same species.
This paper is based on an investigation, during the past two years, into the tree-hole breeding mosquitoes at Livingstone in Northern Rhodesia with particular reference to the endoparasites of the larvae. As a thorough survey is being carried out in northern Barotseland, where yellow fever has been suspected (1943), the present writer submits these observations in the hope that his work in this part of the Zambesi valley may be of assistance to investigators in other areas.
The most important insect pest of cultivated olive in GraaffReinet is Argopistes sexvittatus Bryant (Halticidae). A descriptionption of the various stages of the beetle, and an account of its life-history, are given. Control measures are discussed and suggested.
The effect of moth density upon the reproductive rate of Ephestia kiihniella is discussed in the light of experimental data. It is shown that the reproductive rate increases in direct proportion to the number of moths per unit area until an optimum density is reached, after which a rapid decline in eggï¿½laying takes place. The latter is negatively correlated with the degree of overcrowding.
In 1939 studies of the exoskeleton of the Orthopteroid Insects, classified by J. Omer-Cooper (1938) as Phasmida, Dictyophora and Saltatoria, were commenced with the object of testing the validity of his conclusions. The unsatisfactory state of our knowledge of the tentorium soon became apparent. It appeared to the writer that a thorough investigation of this structure would be of service to entomologists and might also prove useful in assessing the various schemes of insect classification which have been put forward. The present paper is a preliminary study of the three groups originally studied, but it is felt that before any certain conclusions on taxonomic questions can safely be discussed, a much wider survey is essential.
Several species of codling moth parasites are being reared in the laboratories of the Fruit Research Station on larvae and pupae of the codling moth or on alternate host species in connection with biological control experiments. While the provision of host material in quantity is obviously a primary consideration, the question of efficient utilization of the host is scarcely less important.
In the course of studies on parasites and the biological control of various insect pests in Palestine, the writer obtained several species of Encyrtidae which may be of interest to students in other countries. It is the intention of the writer to record these species in a series of papers as his study of them progresses. In the present paper one new species is descriptionbed, as well as the males of two other little-known species. New host records are given of two others.