It is known that, in solutions of some organic solvents such as pyridine, chloroform, ethylene dichloride and acetone, rotenone changes by oxidation to various derivatives, giving the solution a characteristic yellow colour (Jones & Haller, 1931). There is an accompanying loss in toxicity. Now that various intermediate solvents for rotenone in oils are being studied, it becomes of interest to know the stability of rotenone in these solutions.

During a general survey of malaria in Transjordan, which was carried out in the summer and autumn of 1942, the Anopheline here discussed was found to be widely distributed and often common. It was first seen as an adult female, then considered to be Anopheles (Myzomyia) turkhudi, Liston, 1901, brought from Amman, Transjordan, in May 1942 by Capt. H. F. West, R.A.M.C. It is of value to describe the present material and compare it with such descriptions of the other members of the turkhudi group as are available to me at the moment, though it is considered that in no respect does it differ widely enough from A. (M.) hispaniola, Theobald, 1903, to be accorded more than varietal rank within that species.

1. A detailed technique is described for the routine determination of the carbon dioxide output of samples of grain. The concentration of carbon dioxide produced in the intergranular air during incubation for 24 hours at 25°C. is known as the “carbon dioxide figure” of the sample.

2. Suggestions for relating the carbon dioxide figure to potentialities for future storage are given. A high carbon dioxide figure indicates that the grain is unsuitable for storage.

3. The carbon dioxide figure is largely a measure of insect infestation of the sample and a table is given by which the numbers of various species of insects common in grain may be estimated from the carbon dioxide figure.

4. Theoretical considerations affecting the carbon dioxide figure are discussed as far as available knowledge permits.

5. Data obtained in the laboratory during development of the method are presented, and show it to give a useful measure of the amount of infestation.

This work forms part of the programme of the Pest Infestation Laboratory. Thanks are due to Dr. Lucas for making an independent test of the method and for allowing us to use his data.

The genus of Pyralid (Crambid) moths to which Diatraea lineolata belongs is one of considerable size, containing fifty-one described species from the New World (Box, 1931, 1935a), and together with the Old World genus Proceras which, according to Tarns (1942), should be regarded as distinct from Diatraea, includes a fairly large number of major pests of cultivated grass crops in both hemispheres, the most notorious being D. saccharalis (sugar-cane moth-borer).

Most of this paper is occupied with the description of a method for evaluating the influence ol temperature, recorded in the field, on the rate of development of the eggs of a grasshopper (Austroicetes cruciata). When the conventional methods of temperature summation were used, important errors were introduced because:—

(a) The temperature in the environment of the insect may be different from the temperature in the meteorological screen.

(b) The arithmetic mean of the maximum and minimum temperature may not be an adequate estimate of the true mean temperature for the day.

(c) The relationship between temperature and the rate of development of the organism over the range of temperature used, was not linear.

(d) Development may proceed for less than 24 hours of each day.

♂♀. Derm black, with uniform dense grey scaling that has a coppery reflection.

Head separated from rostrum by a narrow bisinuate stria; frons depressed below the level of the eyes and separated from them by a deep incision on each side, obliquely striolate and with a deep median sulcus; eyes moderately convex, extended sharply backwards for about one-third of their length, the orbit not projecting on the hind margin. Rostrum very slightly longer than its basal width, widest at base, gradually narrowing for two-thirds its length and thence more rapidly; dorsum broadly depressed, with longitudinally confluent punctures and a fine median carina. Antennae piceous; scape slightly exceeding hind margin of eye; funicle with joint 1 nearly twice as long as 2,3–7 subequal, about as long as broad and slightly widening distally. Prothorax nearly twice as broad as long, unusually flat, being only gently convex transversely, widest at the strongly arcuate base, the angles of which project laterally, with the sides almost straight and rapidly converging anteriorly, the apical margin being deeply sinuate on each side behind the eyes; dorsum flat longitudinally in the middle, densely squamose, each scale covering a minute granule. Elytra ovate, broader in ♀, widely sinuate at base, which is marginate, with the lateral angles projecting outwards and forwards, and the sides sinuate behind the angles; the dorsal outline moderately convex, sloping at the base; the shallow striae containing close deep punctures, which show through the scaling though partly covered and disappear behind, where the striae become deeper; intervals almost flat, with minute inconspicuous recumbent setae. Legs piceous, with dense concolorous scaling and their lower edges with a fringe of stiff erect setae; front tibiae compressed, with the outer edge carinate and the external apical angle produced laterally, the spines on the apical margin much reduced; hind tibiae with the inner face flattened and sinuate on the apical half, the corbels bare and ascending the dorsal edge more than usual, with the upper end angulate. Venter squamose laterally, but clothed elsewhere with dense stiff suberect setae.

In Northern Nigeria many of the streams are choked with the Palm, Raphia sudanica, which affords excellent conditions for Glossina tachinoides. The mid-ribs of the palm fronds provide long, straight, light poles which are invaluable for roofing in a country where small straight timber is non-existent.

In areas where the palms grow to a good height, there is an important local pole-cutting industry which results in the cutters coming into close contact with tsetse. A high incidence of sleeping sickness is often associated with villages engaged in this trade. The usual solution of clearing the stream-banks of vegetation is obviously undesirable in these cases, and the following method of control has therefore been devised.

In 1935, Dr. Anderson made a sleeping sickness survey of the Kudaru District of Zaria Emirate, Northern Nigeria, where he found a high incidence of the disease. In the extreme case of the small hamlet of Sambo, he recorded a 70 per cent, infection rate among the 43 inhabitants.

The writer followed up this survey with an entomological investigation in the late dry season, and paid particular attention to. this hamlet.

Cow dung was found to be suitable for breeding M. domestica vicina.

The dependence of the duration of development on the temperature was investigated for all stages of development and could be suitably expressed by the formula of an equilateral hyperbola.

Adult longevity was studied under various conditions of temperature and humidity. The maximum length of life in captivity was found to be 106 days, the average being 20–30 days. As the temperature rises, longevity decreases. Above 20°C, life is longest at a relative humidity of 42–55 per cent., whereas below 20°C., a lower humidity (30–40 per cent. R.H.) is favourable.

Fertility was studied from the point of view of size of individual egg hatches and the frequency of oviposition.

The mean number of eggs deposited by a female fly per day of adult life does not depend on the duration of adult life and does not change considerably during life.

The sugar-cane scale, Aulacaspis tegalensis, Zehnt., has been known to exist in Mauritius since the year 1899, when de Charmoy recorded it for the first time in the Island.

The species was described by Zehntner in 1898 from Java on sugar-cane, since when little has been recorded of its geographical distribution. In 1921, Ferris recorded it from Formosa. In 1938, D. d'Emmerez de Charmoy, jr., called the attention of the planters of Reunion to the damage caused by this scale on sugarcane, and the author had suspected its presence there many years previously. In Java it was considered of minor importance by Zehntner in 1897. In 1911 Van Deventer drew attention to the damage it caused in Java, and in 1915 van der Goot recorded a serious infestation in the experimental cane fields of the Java Experimental Station. Apart from these records, it has not been reported from other sugar-cane growing countries.

A method for fumigation experiments has been worked out, and preliminary tests on 21 substances are reported. The dosage-mortality relationships of about 10 of these arc being worked out in some detail, while six have been chosen for practical tests. It is hoped to make reports on these two aspects later.

The following is a description of a new mealy-bug occurring on cacao in the Gold Coast, which is reported by the collector, Mr. H. E. Box, to be one of the Coccid vectors (Ferrisia virgata being another) of the “swollen-shoot” virus disease of cacao.