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.

During the last year, while I was engaged in work on stored product pests for the Infestation Branch of the Ministry of Food, the necessity arose for identifying Lepidopterous larvae damaging stored food. It was soon found that with few exceptions the available descriptions of these larvae are quite inadequate, as they are usually based entirely on colour, and it became necessary to employ more precise methods. The arrangement of the setae (chaetotaxy) together with other structural characters proved to be reliable for distinguishing the species. By these means those concerned should be able to identify without undue difficulty most of the moth larvae they are likely to encounter. Altogether 35 out of some 70 species which have been found associated with stored products in all parts of the world, can be positively identified by means of the keys and descriptions given in this paper. These 35 species include all the more important British ones and seven which have not yet been recorded in Britain, viz. : Celama sorghiella (Riley), Cryptoblabes gnidiella (Mill.), Acrobasis caryae, Grote, A. juglandis (Le Baron), Etiella zinckenella (Treit.), Pyroderces rileyi (Wals.), and Anchonoma xeraula, Meyr.

The data concerning the distribution have been supplied by Dr. A. Steven Corbet and Mr. W. H. T. Tarns and are based on authentic material in the British Museum. The order in which the families and lower systematic categories are arranged in the keys and descriptions is governed only by convenience and not by phylogenetic considerations, e.g., the most primitive family, Tineidae, is dealt with last.

It was decided in May 1942 to make a survey of the Culicine mosquitos of Syria and the Lebanon, but the more important work dealing with the Anophelines prevented a complete and detailed one of the whole of Syria, though that of the Lebanon is more or less complete. Where only one or two records exist for any particular species, it cannot be presumed that these mosquitos are not common, and a subsequent detailed survey would probably reveal not a wider distribution of some species but also the presence of others not recorded here.

Whenever possible, eggs and larvae were bred out and permanent mounts made of the larval and pupal skins, and consequently identification of most of the species was based on larval, pupal and adult characters.

The identification keys used were taken from Marshall's “ British Mosquitoes ” 1938, and Kirkpatrick's “ Mosquitoes of Egypt ” 1925. It was found necessary to alter and to make new additions to these as they did not contain all those species found to be present.

I wish to thank Lieutenant-Colonel MacDonald, R.A.M.C, Malariologist, for permitting me to complete this work, Major H. S. Leeson, R.A.M.C, Entomologist, and Major O. Theodor, R.A.M.C, Entomologist, for their invaluable help in the construction of the keys and the confirmation of the species.

Uranotaenia unguiculata, Edw.-A single female was found resting among the vegetation in the daytime at Ammiq swamp in November, and a single larva was taken there in October. The breeding place was a small clay pit, 6–8 inches deep and containing green algae and a certain amount of vertical vegetation. U. unguiculata has not been found in any other part of Syria or the Lebanon.

Diapause should not be confused with simple inhibition of growth due to cold.

The embryo of the grasshopper, Austroicetes cruciata, enters a state of diapause a few days after the egg is laid. The diapause is obligate like that found in the eggs of Circotettix, rather than facultative like that found in the larvae of Platyedra. These types of diapause should be regarded as two extremes of the one phenomenon rather than two distinct phenomena.

Diapause was eliminated when the egg was exposed to adequate low temperature for an adequate period when the embryo was at a suitable stage of development. If the period at low temperature was inadequate, or if the embryo was not at a suitable stage of development when the exposure to low temperature occurred, diapause was only partially eliminated. In such cases, the exposure to low temperature resulted in an abnormal growth by the embryo when the egg was returned to a favourable high temperature, but development was not completed.

The influence of low temperature on the elimination of diapause was due chiefly to changes which occurred in the yolk during exposure to low temperature. Thus yolk which had been modified in this way became suitable for the nourishment of the embryo, and it no longer obstructed katatrepsis. This explanation of the nature of the obligate diapause in the eggs of Austroicetes brings this phenomenon into line with the facultative diapause in the larvae of Platyedra, which has been shown to be associated with the nourishment of the larva.

Diapause was eliminated most rapidly at temperatures between 6°C. and 13°C. The embryo grew most rapidly at about 30°C. ; below 13°C. growth practically ceased. The absence of overlapping of the temperature ranges for these two processes may explain the presence of diapause in Austroicetes. The occurrence of a less pronounced diapause in the eggs of Melanoplus may be due to a partial overlapping of the temperature range for the two processes. Similarly the absence of diapause in the eggs of Locusta may be explained on the assumption that in this species the two processes proceed over the same temperature range.

1. A new species of aphis, Aphis (Doralis) cognatella, found on Euonymus europaeus is described and compared with Aphis (Doralis) fabae, which it closely resembles. This new aphis is brown in colour and has long hairs.

2. Two individuals, intermediate in character between oviparae and sexuparae, are mentioned.

3. Transference experiments, carried out under somewhat artificial conditions, show that although the aphis is normally found on Euonymus sp., it can exist for some time on Rumex obtusifolius, R. crispus, Chenopodium album, Capsella bursapastoris, Arctium lappa, and Beta vulgaris (flower stalks), which are also host plants of A. fabae, but it does not colonise Vicia faba.

4. The sexuparae are apterous and produce males, oviparae and apterae, thus differing from A.fabae, in which there are two sexuparous forms, one an alate gynopara and the other an apterous form found on the summer hosts.

5. Olfactometer experiments give no indication of any olfactory response to the odour of E. europaeus leaves.

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.

An outbreak of body lice might require several control measures according to circumstances. Two types of fumigant action have been investigated in the laboratory and the field :—

(1) House fumigation for disinfesting typhus-contaminated premises.

Lice were fairly similar to bed-bugs in their resistance to the fumigants tested. In practice, 16 oz./l,000 cubic feet of hydrogen cyanide will kill lice and eggs : 2 lb. of sulphur/1,000 cubic feet is also successful if the wind is not strong.

(2) Bin fumigation of garments by saturated vapours.

The saturated vapours of solids such as naphthalene and paradichlorbenzene are extremely slow in action ; even with 20 hours exposure at 20°C. they are unreliable. Liquids such as heavy naphtha or trichlorethylene are much more promising.

For reading and criticising this paper I am grateful to Professor Buxton in whose department the work was done. My thanks are also due to the Medical Research Council for a grant.

While assisting my late husband, Dr. M.A. Volkonsky, in his work on locusts at Algiers, I accumulated considerable practical experience with regard to the technique of mass breeding of locusts in cages, as well as making some observations on their behaviour. The following notes do not pretend to be scientific, but they may be of interest and value to other workers.

1. These studies were originally intended to form the basis of a world monograph of the Siricidae ; such a work cannot be completed under present circumstances.

2. Two ratios are introduced as useful characters for separating species : the ovipositor/forewing ratio and the sawsheath/ovipositor ratio. These ratios were obtained from all specimens of all the species represented in the British Museum collections and the results are tabulated. They were found not to vary with the size of the insects.

The former ratio is specially useful in the genus Urocerus, which has a long ovipositor, and the latter ratio in the genus Sirex, which has a shorter ovipositor.

3. Keys are given to the genera of the world. Of Semenov's new genera, Xoanon is accepted but not Xanthosirex. A new genus Eriotremex is erected for certain Indo-Malayan species previously included in Tremex.

4. Keys are given to the European species, which are compared critically with related species from other parts of the world. A key to the species of Eriotremex, gen. nov., is also given.

5. Sirex noctilio, F., and S. juvencus, L., are recorded for the first time from North America and S. cyaneus, F., from the continent of Europe. The common Urocerus of the northern Palaearctic region is shown to be more closely related to the Nearctic U. gigas flavicornis, F., than to the central European U. gigas gigas, L., and is treated as a new subspecies—U. gigas taiganus, subsp. nov. U. gigas tibetanus, subsp. nov., is described from the Himalayas. U. sah, Mocsáry, is treated as a subspecies of U. augur, Klug, and U. cedrorum, Smith, as a synonym of U. augur augur, Klug.

6. The British Siricidae are discussed, and it is suggested that U. gigas taiganus, subsp. nov., and the form of S. juvencus, L., with entirely black antennae may be native in the Caledonian forest.

7. It is argued that modern Siricidae could not have been derived from the Jurassic Pseudosiricidae.

8. The known Oriental and Himalayan Siricidae are listed and discussed. Urocerus multifasciatus, Takeuchi, and Eriotremex formosanus, Matsumura, are mentioned as two species originally described from Formosa but shown also to occur on the mainland. Urocerus niger, sp. nov., is described from the Himalayan region, and the name Eriotremex malayanus, sp. nov., is given to a form described without a name by Forsius from Malaya.

9. Several errors in previous work on Siricidae are corrected.

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 pyrethrins, nicotine, rotenone and a derris resin have been tested in the laboratory under standard conditions for their ovicidal effect. The test-subjects were : Pieris brassicae, Plutella maculipennis, Aphis rhamni, Ephestia kühniella and Sitotroga cerealella. Notes on the technique of egg production are given for these species. In the majority of the tests made a water medium containing acetone together with sulphonated lorol as a wetting agent was used.

It has been shown that all these products are toxic to the species on which they were tested. Lauryl thiocyanate, β-butoxyβ'thiocyanodiethyl ether and 3 : 5 dinitro-o-cresol were included as substances of recognised ovicidal value for purposes of comparison.

All the above insecticides derived from plants compared favourably in their toxic action with the synthetics. In two instances during tests on eggs of Ephestia kiihniella, data were obtained enabling a satisfactory statistical comparisdn of relative potency to be made. In the first of these, the pyrethrins were found to be 8·45±1·47 times as toxic as 3 : 5 dinitro-o-cresol, while in the second the pyrethrins were found to be 2·66±0·26 times as toxic as a Derris elliptica resin (rotenone content 37–40 per cent.). It therefore appears that both the pyrethrins and the derris resin were more toxic, weight for weight, than 3 : 5 dinitro-o-cresol which is recognised as one of the most potent ovicides.

The above vegetable poisons were found to be toxic not only to eggs developing in a few days without a diapause, but also to those of Aphis rhamni, a species of overwintering egg. The tests on A. rhamni were made at the time the eggs were just starting to hatch. The same result might not have been obtained with eggs at an earlier stage of development.

Observations were made on the effect of the different insecticides on the development of the egg. This effect appeared to differ with each substance, either qualitatively or quantitatively, but within the limits of the experiment it seemed to be independent of the species of the egg.

This paper has been written in response to a request for determinations of certain parasites of wood-boring beetles in Queensland, Australia. The description of a new species of Monolexis entailed rather more research than was expected and has led to the expression of a few opinions of an exploratory nature on the status of the subfamily Hecabolinae. Altogether one new species in the Doryctinae and six (including one new genus) in the Hecabolinae are described.

The types of all new species are in the British Museum.

Pyrethrum-oil films were tested in various forms on plaster substrata against the tick, Ornithodorus moubata. The insecticide was most effective if applied :—

1. Concentrated rather than dilute.

2. In a medium rather than a light petroleum oil.

3. As an emulsion in Lanette Wax Solution rather than in oil alone.

4. With an irritant (such as 4-chlor-2-methyl-phenol) present in the solution.

This short review is incomplete in so far as it deals only with the material received by the Imperial Institute of Entomology for identification and that which is contained in the collections of the British Museum. A list of the species unknown to me is given at the end of the paper.

Nine new species and one new variety are described.

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.

i. A four-year survey, involving the investigation of over 1,000 cases of strike, has been made of the species concerned in sheep myiasis throughout the British Isles. In all regions, L. sericata is the principal maggot-fly. In Scotland, Northern England and North Wales, L. caesar is an important species. Phormia terraenovae has much the same distribution, as a striking species, as L. caesar, except that it apparently does not strike sheep in North Wales ; in the areas where it occurs it follows L. caesar in importance. These two species are apparently capable of acting as primary flies. Calliphora erythrocephala, and, more rarely, Calliphora vomitoria occur fairly generally over the country, but only in very low incidence. Larvae of Muscina spp. have been recovered from only three cases, one each in Scotland, England and Ireland. The two closely related species, L. caesar and L. illustris have only been separated in a few instances, and there is not sufficient evidence for the latter species, but it would seem to be more common in lowland areas than in the north and west.

ii. The incidence of “ alternative ” species, i.e. species other than L. sericata, decreases from north-west to south-east of Britain ; they occurred in 47 per cent. of strikes north and west of a line from Inverness to Glasgow, and in over 20 per cent. of the cases between this and a line from East Lothian to Morecambe Bay, south of the Lake District. In the fringe of hill country east and south of this, e.g., the Cheviots, Pennines and Wales, about 10 per cent. of cases contained “ alternative ” species. Farther to the south-east and south “ alternatives ” were rare.

iii. Within the above belts of territory, the “ alternative ” species appear to have certain common regions which are favourable for the striking habit, although the limits of strike-distribution for each species are apparently not quite coincident. These “ favourable regions ” are discussed in the text. With Phormia terraenovae the habit appears to be restricted to favourable regions, where it occurs in moderately high incidence ; with L. caesar strike occurs in relatively high incidence in favourable regions, but is also present, in low proportion, throughout the country, while the Calliphora species strike in low proportion in favourable regions, and sporadically elsewhere.

iv. Phormia and L. caesar have a higher relative incidence in the first half of the fly season than in the later half ; C. vomitoria may be restricted to the extremes of the season-May, June and September.

A survey of the distribution of Aëdes aegypti and other Culicine mosquitos was made during the dry season of 1942, between 31st March and 15th May. The position of Eritrea gives it a particular interest in relation to the possible spread of yellow fever from Africa to the East. In the west it borders on the Anglo-Egyptian Sudan, in parts of which yellow fever is endemic, and it has a Red Sea coast line of some 600 miles, near the centre of which is the port of Massawa. The Culicines hitherto found include six that are known to be potential vectors of yellow fever.

The topography and climate of Eritrea have been described by Lega, Raffaele and Canalis (1937). The country may be divided into four areas, the eastern and western plains, the mountain slopes and the plateau. The latter, on which lie several of the towns, is from about 1,900 to 2,500 metres (some 6,200 to 8,200 feet) above sea level.

Amongst a collection of Miridae made by Mr. H. E. Box in the Gold Coast, during his work on the insect pests of cacao plantations, is a series representing a new genus and species of Bryocorinae allied to Sahlbergella, Hagl. These specimens were submitted to me by the Imperial Institute of Entomology and are herewith described.