1. Two series of hourly measurements of temperature and light intensity, each extending over 24 hours, were made in artificial pools. One pool contained clear water, one muddy water, one standing grass 1 ft. high and one was completely shaded by papyrus matting at a height of 1 ft. Shade temperature records were kept in a Stevenson screen.

2. The results showed that the grass had a pronounced insulating effect on temperature. The range in the grassy pool was less than that in the screen and less than half than that in the open pool. The grassy pool was warmer by night and cooler by day than the open pool. No essential difference was noted between the temperature cycle of the clear open pool and the muddy open pool nor between the grassy pool with broken shade and the pool receiving complete shade from matting. Maximum light intensity in the grassy pool was less than half that attained in the open pool.

3. It is concluded that not only do the breeding waters of A. gambiae reach much higher temperatures than those of such species as A. funestus, A. coustani and A. pharoensis, but that they also undergo much greater temperature fluctuations.

The seasonal incidence curve of strike is bimodal, and divisible into four phases, the pre-shearing, the shearing trough, the lamb phase, and the late season adult and lamb phase. About two-thirds of the strikes reported by shepherds occurred in the hindquarters area (this term including the rump and hindlegs). In a lowland flock where all strikes were noted over a five-year period the incidence of hindquarters strikes was much lower (43 per cent.). The shoulders area, in relation to its size, is highly susceptible. It appears to be even more common a site in lowland than in mountain breeds. Rather more than half of the reported cases were in adult sheep, and of these more than half were in shorn sheep. Body strikes were relatively more common in shorn than in woolled sheep. Species other than L. sericata (referred to as alternative species) occurred mainly in mountain breeds or their lowland crosses, and more frequently in body than in breech strikes. Alternative species were more or less equally common in adults and in lambs, except Phormia terraenovae, which was practically confined to adults. The occurrence of alternative species was significantly associated with the type of grazing, and also with the vegetation type on the grazing ; the partial association with vegetation type, with pasture type constant, suggests that presence of bracken and/or heather is closely associated with the conditions resulting in alternative species striking sheep.

The attraction of insects to light is proverbial, and allusions to it occur throughout the literature, showing that it has always excited the interest and curiosity of mankind. Yet it has not received the scientific treatment it deserves. Entomologists have, it is true, investigated it in recent years, but with no great success. The reason for their failure is not far to seek. The method adopted in the beginning was, unfortunately, that of the light-trap, which led immediately to a utilitarian and unscientific approach. The literature that ensued so far from elucidating, merely obscured, the true nature of the phenomenon.

This is clearly shown by the fact that in nearly every investigation the method is to expose one or more traps of various design and complexity in fields at night, the catch being counted and classified in the morning. This is quite a harmless hobby and may even be of some use in indicating whether one trap is better than another and, so long as it is used for this purpose, there is no fault to be found with this method. But this is not the case. The prevailing tendency has been to proceed from observations of the catch not merely to conclusions regarding the relative efficacy of light-traps, which would be legitimate, but to deductions concerning the laws and nature of phototropism which is fallacious. Thus, to take a common instance, a species A is caught in considerable numbers while another species B, though known to be present, is not trapped in any quantity, and the conclusion frequently drawn is that A is more strongly photo-positive than B. The objection is that the investigator knows nothing about the density and distribution of the species concerned in the vicinity of the traps ; he is, therefore, unable to go beyond the observed fact that his trap took more of A than of B, and is not entitled to draw conclusions regarding the relative photo-positiveness of the two species since one may have been more favourably situated or far more numerous than the other in the field.

The types of the species described below will be deposited in the collection of the British Museum (Natural History), and the paratypes are in my collection.

I wish to acknowledge here the valuable assistance received from Dr. W. J. Hall on many occasions.

The species described here, Anagyrus beneficians, sp. n., can easily be distinguished from the great majority of species by the colour of the flagellum, which is completely black. Another good diagnostic character that will aid in the identification of this species is the arrangement, in six longitudinal rows, of the coarse dark setae on the frontovertex.

Relatively few species of Anagyrus have been described which have the flagellum wholly black. Among these species are : nigricans, Perkins, fusciventris, Gir., nigriflagellum, Gir., subnigricornis, Ishii, punctifrons, Timb., marquesanus, Timb., orbitalis, Timb., and longicornis, Mercet. Specimens of only one of these species are available for study, namely A. fusciventris, Gir. The species described as new is very much like A. fusciventris in all the major structural characters. Both belong to a group of species characterised by a very short ovipositor. These two species differ in some of their minor characters. In A. fusciventris, the tips of the forewings appear hyaline or silvery, due to a narrow band of refractive cilia at the apex of the blade. In A. beneficians, the forewings are uniformly ciliated. The three species described by Timberlake, from the Marquesas Islands, punctifrons, marquesanus, and orbitalis, have the head, thorax, and abdomen black, in colour unlike A. beneficians. Likewise, the species described by Girault, from Australia, A. nigriflagellum, differs in coloration, the head and thorax are orange yellow. In A. nigricans, the apex of the pedicel is reddish, while in the new species it is wholly black. In A. subnigricornis, the scape is marked with white at the base as well as near the apex, and the frontovertex at the anterior ocellus is as wide or slightly wider than the head width, in which respects it is unlike A. beneficians. In A. longicornis, Mercet, the abdomen is truncate at the apex, the pedicel reddish, and the head and thorax yellow ; all of which separate this species from A. beneficians. In this brief resumé it is possible that some species have been overlooked which have the flagellum completely black. However, the conditions under which Anagyrus beneficians originally existed and its subsequent introduction into Kenya Colony strongly indicate that the species has not been described previously.

Anagyrus beneficians, Compere, obtained in small numbers from shipments of other parasites from Uganda, proved to breed readily in the laboratory.

Numbers were reared, liberated and established on mealybug in coffee districts and native reserves in Kenya.

It is one of several parasites responsible for a marked reduction in the severity of the mealybug.

This paper brings together all the species of Microphanurus from the Ethiopian and Indo-Malayan regions that I have written about during the last eight years. I have found that the fauna of neither region could be studied in isolation if a proper understanding of the taxonomic relationships and host-preferences of the genus were aimed at.

The key contains all the species from the regions concerned of which the types or at least authentically named specimens are in the British Museum. Two new African species are described.

For the identification of the Hemipteron, Atelocera stictica, Westwood, and for other information I am much indebted to Mr. W. E. China.

One and a half tons of Plate wheat, of water content 12·9 per cent., infested by insects, especially the small form of C. oryzae, Rhizopertha, and Laemophloeus, were placed in an iron bin in May 1941. By the following November the wheat was heating near the surface and was extremely heavily infested in the 25 cm. surface layer. The carbon dioxide concentration beneath this layer exceeded 10 per cent.

During December the hottest depth in the grain was nearer to the surface. The temperature reached 37°C, 27°C. above air temperature. Many weevils came to the surface in early December and walked off the grain. Then in mid December the grain temperature fell rapidly and reached air temperature by the end of the month. A week later many insects were still alive, but by March 1942 very few living insects were found. The carbon dioxide concentration fell rapidly but rose again in March, presumably due to the increased grain water content and the respiration of micro-organisms.

In 1942, conditions became suitable for insect activities in April, and by May an infestation had started, this time predominantly C. granaria. Laemophloeus was also present, having apparently survived the winter in the bin, but neither C. oryzae nor Rhizopertha had survived. Insects were confined to the surface layers by the carbon dioxide present deeper in the bin. Consequently heating did not occur in 1942, and when the grain was moved in October 1942, its temperature was falling after reaching a maximum of 27°C. in August.

The effect of the presence of insects upon grain is discussed. It is shown that the conditions arising in the bin resemble those in general storage, except that the use of an open topped bin with airtight sides and bottom caused a much greater accumulation of carbon dioxide than is usual.

It is suggested that if the grains infested by weevils are buried in the bulk, heating is likely to occur, whilst if the infestation is superficial the grain may not heat. The part played by weevil larvae in the heating of grain is stressed.

It is suggested that regular examination of samples of grain from deep in a bulk should be made for insects and that all bulks should be examined soon after being placed in position. Routine temperature and water content readings should be made at points deep in the grain and about 10–20 cm. below the surface.

The damage done to cacao (Theobroma) in West Africa by certain species of Capsidae has been described by Dudgeon (1910), Cotterell (1926) and Voelcker and West (1940). At the start of a selection programme aimed at developing strains of cacao resistant or tolerant to such damage, it was considered necessary to develop a laboratory technique for testing the palatability of selections. It is noticeable in the field that certain trees appear consistently to escape attack ; this might be due to some form of unattractiveness to the Capsids. One of the most obvious forms of preference which seems to be shown by these bugs is that of Sahlbergella theobroma for seedlings and young trees up to about six years old and that of S. singularis for mature trees. Indeed until very recently there was no field record of S. singularis attacking seedlings in the Gold Coast. Conversely, attacks by S. theobroma on mature trees are confined almost entirely to pods, while the other species causes severe damage to shoots. Dudgeon (loc. cit.) reports old trees “ exhibiting damaged bark and dead branches ” in the presence of S. theobroma, but these may have been feeding on pods.