The paper deals with the control of insects by hand-collection. An experimental study of the method as used against Antestia on coffee in Kenya is described. The rate of increase of the yield of insects collected falls off in a definite and measurable manner as the time spent on the work increases. The formula for the curve fitting the results is P = 100(1 − (V.e.)−t) where “ P ” is the percentage collected of the total Antestia present, “ t ” is the time spent collecting, and “ V ” is a coefficient which has different values according to the conditions prevailing. In practice one careful experimental picking provides data for the calculation of the formula which may be used to determine the cost of hand-picking any percentage.

The results show that in theory 100 per cent. of the insects can never be obtained by hand-picking, and that in practice the cost of picking an adequate percentage is almost invariably prohibitive.

It is probable that the experimental results obtained will prove valid in other cases of hand-picking. Much of the expenditure on this method is unproductive.

Details of a thorough long-continued attempt to control Antestia on thirty-five acres of coffee by hand-picking are given. The attempt proved unsuccessful, and it is suggested that it may actually have been responsible for the maintenance of the severe attack.

The kind co-operation and assistance of a number of coffee planters are acknowledged. Except for the first experiments in 1933 Mr. H. Naismith Jones assisted me throughout, and the investigation owes a great deal to his careful supervision of much of the field work.

For the biological study of Tachardia lacca, Kerr, it is of importance to have, so far as possible, a complete knowledge of all the insects that live in relation with it—predators and parasites of the Coccid, parasites of the predators and hyperparasites. This biological complex begins to be better known, owing to the studies of several entomologists in India, especially at the Indian Lac Research Institute at Namkum.

In the course of some work at Rothamsted on the activity and abundance of insects, in which a light trap was used as a method of estimating the numbers of insects in a state of activity, it appeared advisable to have a further trapping method which did not depend on phototropic response for its efficiency. A rough design for a mechanical trap was therefore drawn up by the senior author.

During investigations on the ecology of Aphids infesting the potato crop it became necessary to study the precise effect of the different meteorological factors upon migration. Traps, treated with adhesive material, which depended on a wind-vane to keep them at right angles to the direction of migration were first used but proved unreliable, since it was found that aphis migration attains a maximum when there is little or no wind. Kites, also, proved impracticable for the same reason. It was, therefore, essential to construct a trap which worked independently of meteorological conditions. I am indebted to Dr. C. B. Williams and Mr. P. S. Milne, of Rothamsted Experimental Station, for the opportunity of discussing and examining the construction of their electrical mechanical trap, described in the preceding paper, which formed the basis of one constructed at the College Farm, Aber, near Bangor. Since, however, the village of Aber has no electricity supply it was necessary to alter, materially, the mode of construction in order to drive the trap by water-power. For this reason and, since the modified form can be used in districts where there is no electricity supply, it was suggested that the present account of the water-power mechanical insect trap should be published along with the description of the Williams and Milne trap. I am, therefore, grateful to the authors of the preceding paper for the opportunity of seeing their manuscript, thus avoiding, by reference, repetition of the description of several parts.

Cocoons of Diprion sertifer, Geoffr., containing nearly eight millions Microplectron fuscipennis, Zett., were collected in Europe in 1934 and despatched to Canada for the control of the Spruce Sawfly, Diprion polytomum, Htg.

This parasite is widely distributed throughout Europe as a primary parasite of several species of pine sawflies of the genus Diprion.

A full account of the biology and a detailed description of the various stages is given.

In the laboratory it was reared in large numbers on the cocoons of D. polytomum from Canada.

Its chances of success in Canada depend on its acclimatisation and the accessibility and quantity of host material. Its tremendous fecundity and rapid rate of increase are greatly in its favour.

The excretions of the blowfly maggot, Lucilia sericata, have been found to contain a potent bactericide, and the technique for the collection of this material is given. There is evidence that other insects besides the one investigated may also produce this substance.

The active principle is not destroyed by autoclaving at 10 pounds' pressure for 20 minutes and desiccation does not inactivate it.

The bactericidal action of the substance was demonstrated by tests on seven species of bacteria, most of which are of aetiological importance in osteomyelitis and other suppurative infections. The lethal action against such organisms seems to be an important factor in the good results obtained with maggot therapy.

The work seems to open a field in which interesting investigations could be conducted with possibilities of producing other new and useful disinfectants from living organisms.

Dermatodes cinchonae, sp. n.

♂♀. Derm black or piceous, with uniform dense brown scaling above, becoming paler laterally and beneath.

For several years the Farnham House Laboratory of the Imperial Institute of Entomology has been making a study of the parasites of Diprion spp., in order to acclimatise the most important of them in Canada. Dr. K. R. S. Morris has been specially engaged on this investigation in Czechoslovakia and Hungary, and this year (1935) has discovered some parasitised eggs of Diprion sertifer, Geoffr. Almost at the same time, other eggs of the same host, sent from Sweden, were found to be parasitised by some Chalcids, but belonging to another species. Experiments are actually being made to breed and acclimatise these two species in Canada. Both are Chalcids belonging to the family Eulophidae, sub-family Entedoninae. As very little is known about these egg-parasites of sawflies, we are giving notes and descriptions of these two species, of which one proved to be new.

Camponotus compressus, the common black ant (fig. 1), is one of the most abundant and best known species of ants in South India. The worker is a large jet-black ant ranging in length from 6 to 16 mm. with moderately large eyes, brownish legs and antennae and a prominent shining abdomen. These ants live in enormous communities, travelling long distances from their nests, and are active at all times of day and night. Though ordinarily of a peaceful disposition, when alarmed or disturbed they may display a tendency to be quarrelsome.