Following the method of procedure already outlined, the life-history of Smynthurus viridis, its bionomics in sensu stricto, and the influence of environmental factors under controlled laboratory conditions, having been considered, the next step is an examination of the seasonal cycle of events as occurring in nature. Part II is, therefore, devoted largely to an analysis of the field data, coupled with an interpretation thereof as substantiated by critically planned and controlled laboratory experimentation; this reinforcement being rendered necessary on account of a multiplicity of factors acting simultaneously in nature. The chief difficulty in an investigation of this kind (as with all problems concerned with fluctuations in the numbers of organisms) lies in the fact that there are few methods for obtaining quickly and easily an accurate quantitative sample of the numbers and kind of organisms; and, secondly, there is the difficulty of finding (in a long-inhabited country like Britain) a “normal” environment, i.e., one in which purely natural agencies have been allowed free play over a sufficient interval of time to allow a state of equilibrium to have become established between the various members of the community to which Smynthurus belongs, in their relationship to the physical factors of the environment and to each other.

A Section of the Division of Economic Entomology of the Commonwealth Council for Scientific and Industrial Research is devoted to the attempted control of noxious weeds by means of their insect enemies.

Early in the month of January 1931 a large swarm of the Pyrrhocorid bug, Melamphaus faber, F., invaded trees of Hydnocarpus anthelmintica, Pierre, and H. wightiana, Blume, at the Government Experimental Plantation, Serdang, Selangor, Federated Malay States.

From the formation of the Froghopper Investigation Committee in 1925, the chemico-ecological relations of the froghopper have engrossed the greater part of the attentions of the scientific workers on this pest, and a considerable volume of precise knowledge on these lines has been accumulated by Hardy and his colleagues. From representations made by Dr. J. G. Myers, however, the necessity for more strictly entomological work was realised, work which should be “comparable in precision and in extent with that already amassed by the Committee.” The present paper is an account of a part of the work undertaken with this somewhat ambitious end in view. The studies of which an account is given here were commenced in September 1929, but owing to absence on duty abroad, the real beginning of the work did not occur until March 1930.

(1) It has been assumed that parasites oviposit in their hosts purely at random, not discriminating between healthy hosts and those already parasitized.

(2) Only one Collyria calcitrator can develop in each Cephus pygmaeus so that parasites of this species ovipositing in hosts already parasitized endanger or doom their progeny.

(3) 3,761 larvae of Cephus pygmaeus were dissected; 1,049 were unparasitized and 2,712 were parasitized by Collyria calcitrator; 2,195 contained one, 332 two, 98 three, 49 four, 18 five, 7 six, 4 seven, 5 eight, 2 nine, 1 eleven, and 1 sixteen parasites.

(4) These observed data do not agree, even when corrected for several factors, with the values to be expected from random distribution of the eggs one at a time.

(5) The observed data indicate a degree of discrimination on the part of the ovipositing females.

1. The damage done to coffee by Antestia lineaticollis, Stål, is shortly described and notes on its life-history are given.

2. It is parasitised in the egg-stage by two important species of Proctotrupoid parasites, the percentage of parasitism usually varying around 80 per cent. and in one case quoted being as high as 91 per cent.

3. Of the control measures employed, contact-spraying has not proved satisfactory; hand-picking of the bugs and egg-clusters and liberation of the parasites are widely practised and, though troublesome and expensive, are of considerable value; another method of value and widespread adoption has been called the “poison-baitspray” method. This is described in detail; it consists in the application of a stomach-poison in the form of a solution of sodium arsenite and sugar to the tree by spraying. Laboratory observations show that the insect imbibes the poisoned solution by lifting the proboscis into small drops on the leaf surface, and there is a definite kill due to the use of this poison.

4. In Kenya, its use commercially, while often of proved value, has not been invariably successful. Experiments showed that the egg parasites of the bug were strongly attracted by the poison spray and quickly died after feeding on it. It is suggested that this may be the cause of some of the unsuccessful results.

Various instances of the formation of a chitinous capsule around parasites in mosquitos have been described in literature. Worms as well as Protozoa, Hyphomycetes and bacilli have been seen encapsuled in this way.

The male of which the peculiar hypopygium is shown in fig. 1 was bred from a lot of eggs received in March 1931 from Prof. Snijders (at that time in Medan, Deli, East Coast of Sumatra). Other males which had hatched from the same eggs were examined, but they had a normal hypopygium.

This paper is my report of a year's work on the sheep blowfly problem at the Farnham House Laboratory of the Imperial Institute of Entomology. The investigation had a two-fold aim. Its immediate object was the development of a satisfactory large-scale methodof rearing Alysia manducator, and practical results in the form of shipments of the parasite were required. Its ulterior purpose was the accumulation of exact quantitative data on the interaction of a parasite and its host.

Some years ago the writer published an account of the bionomics of the two species of Eumerus whose larvae attack narcissus and other plants. In this account it was pointed out that E. tuberculatus, first recognised as occurring in Britain by Collin in 1920, was far more abundant than E. strigatus, which had been described by Verrall in 1901. This finding was entirely contrary to expectation and threw serious doubt upon the accuracy of many previous records of injury to plants in which strigatus was invariably cited as the culprit. At the same time it explained in a large measure the absence of reports of Eumerus attacking onions in Britain, for in those countries in which damage to onions is of common occurrence the predominant species appears to be strigatus. In view of the foregoing, and of the fact that the successful cultivation of onions is exceedingly difficult and at times impossible in regions where attacks by Eumerus are experienced, it is desirable that further information be obtained as to the occurrence of strigatus in Britain.

A long-horned beetle, Cerambyx dux, Fald., is a very serious pest of apricots, peaches, and grafted and wild almonds in Palestine. Its ravages are most probably not confined to these trees and further investigations will undoubtedly enlarge the already important list of food-plants. In localities around Jerusalemsuch as Beit-Jala, Artas, Bethlehem, El Maliha, and Ein Karim (approximate altitude 2,600 feet above sea-level), this pest has been allowed to establish itself over a long period of time and to such an extent that, if immediate and rigid control measures are not undertaken by the growers, apricot and peach trees will, sooner or later, disappear from these localities. These fruit trees can be cultivated without irrigation, which is of great advantage in Palestine, where water is scarce; the fruit fetches good prices both in the local markets and also in Egypt. Their cultivation is therefore of vital importance,especially to the population of the hill country, where conditions of life are difficult and every kind of loss is accentuated. In Jersualem, where almonds, apricots and peaches are planted in household-gardens, not a single healthy tree can be found, and many of them have already succumbed to the attacks of this beetle. In the coastal plain the writer has found this insect in almond trees at Haifa and in apricot and almond trees in villages north of Acre. No records are available of its presence in the coastal plain south of Haifa or in the Jordan Valley.

A study has been made of the small moth-borers (Diatraea), the giant mothborer (Castnia), and the froghopper (Tomaspis) of sugar-cane, in their respective primitive environments, primarily with a view to finding new parasites for them and secondarily to obtain light on their ecology under agricultural conditions.

The original hosts of Diatraea saccharalis are shown to be certain aquatic and semi-aquatic grasses growing at the edge of forest creeks in the Orinoco Delta and of rivers flowing through the Venezuelan llanos, and in lakes of the Greater Antilles.

In the llano habitat D. busckella and D. impersonatella were found under indubitably primitive conditions.

The original host of D. canella, another destructive cane species include two forms of Paspalum millegrana, growing on the Trinidad littoral.

The present paper is the outcome of a visit to Turkey at the invitation of the Turkish Government in the summer of 1931 to study the local locust problem and to advise on the general policy of locust control.