In the subgenus Mochthogenes, only the pupa of Culex (M.) inconspicuosus, Theo., has been described. Since one of us (M.P) has obtained the immature stages of all the known species, including C.(M.) castor, De M., we take advantage of this opportunity to give a key to the pupae. The pelts were all obtained from specimens bred in isolation at Yangambi, Belgian Congo, and the resulting adults identified by means of the male terminalia.

The purpose of this paper is to place on record my notes on the distribution of the mosquitos obtained by myself during an Expedition to Central Abyssinia made, in company with Mr. J. Omer Cooper, from September 1926 to January 1927. We were engaged in collecting insects of many Orders and some other animals, as well as plants, so that it was not possible to devote more than a limited time to Culicidae. Nevertheless, I purposely gave rather special attention to this family and got together a series of some 103 specimens of the adult insects, belonging to 13 (or possibly 14) species. Examples of each species were pinned immediately, when freshly killed, with fine pure-silver pins, while in a few places where large numbers of one species occurred the surplus specimens were placed in spirit. No detailed investigation of the larval or pupal stages was undertaken ; a few examples of these may later be forthcoming among the collection of aquatic organisms which are Mr. Omer Cooper's special province, but they are not dealt with here.

The majority of plant viral disease is transmitted and spread by insect vectors in the field. The small brown planthopper, Laodelphax striatellus (Fallén), is the only efficient vector for rice black-streaked dwarf virus (RBSDV), a devastating plant virus that infects multiple grain crops, including rice, maize, and wheat. Adenosine triphosphate (ATP)-binding cassette (ABC) transporters participate in various biological processes. However, little is known about whether ABC transporters affect virus infection in insects. In this study, RBSDV accumulation was significantly reduced in L. striatellus after treatment with verapamil, an effective inhibitor of ABC transporters. Thirty-four ABC transporter genes were identified in L. striatellus and expression analysis showed that LsABCF2 and LsABCG9 were significantly upregulated and downregulated, respectively, after RBSDV infection. LsABCF2 and LsABCG9 were expressed during all developmental stages, and LsABCG9 was highly expressed in the midgut of L. striatellus. Knockdown of LsABCF2 promoted RBSDV accumulation, while knockdown of LsABCG9 suppressed RBSDV accumulation in L. striatellus. Our data showed that L. striatellus might upregulate the expression of LsABCF2 and downregulate LsABCG9 expression to suppress RBSDV infection. These results will contribute to understanding the effects of ABC transporters on virus transmission and provide theoretical basis for virus management in the field.

A new species of scale insect from coconut trees in Trinidad is described and named Parlagena bennetti. The generic assignment is tentative. A key to the four known species of Parlagena is provided.

Drought is a substantial threat to cereal production under global climatic change scenarios, albeit its aftermath on arthropod pests is yet contentious. To address this issue, demographic characteristics of Metopolophium dirhodum (Walker, 1849) (Hemiptera: Aphididae) were studied on one drought-susceptible wheat cultivar and one drought-tolerant wheat cultivar under different water treatments. Some physiological and biochemical features of wheat cultivars including leaf soluble sugar and proline contents and antioxidant enzymes activities were also investigated. Significant differences occurred in the developmental period, survival, and fecundity of M. dirhodum between wheat cultivars under various water treatments. The impact of intermediate and severe water stress on M. dirhodum was neutral and negative for the tolerant cultivar and negative for the water-susceptible cultivar, respectively. Under severe water stress, on both wheat cultivars, the aphids had low net reproductive rates and finite and intrinsic rates of increase in comparison with those reared on unstressed plants. In total, drought resulted in lower growth of population and reduced survival of aphids. Hence, in the context of projected climatic changes, acute water deficiency could probably result in reducing the abundance and menace of outburst of M. dirhodum. However, it should be noted that the potential likelihood of M. dirhodum eruptions can be drastically affected by the degree of drought intensity and host plant cultivar.

A photographic apparatus is described for obtaining a record of oviposition and larval eclosion at intervals through the night. By the use of electronic flash a negative silhouette image is produced and the method used does not appear to disturb the moths during oviposition. A second apparatus incorporating a moving pen is also described for studying and recording the times of emergence of moths from their pupae.

The recent attack by Pulvinaria iceryi (Sign.) on sugar-cane in Mauritius is discussed in the context of other attacks by sap-sucking Hemiptera in the Mascarenes. P. iceryi is compared with its allies P. elongata Newst., P. saccharia DeLotto, P. sorghicola De Lotto and P. tenuivalvata (Newst.). The name of P. longisqua De Lotto is sunk as a synonym of P. elongata and a key is presented for the five related species.

The genus Cicadulina was established in 1926 (Bull. Ent. Res. 17, p. 43) to hold a new species, C. zeae, China, injurious to maize in Kenya Colony. Later (Bull. Ent. Res., 19, 1928, p. 66) it was shown that Balclutha mbila, Naude, recorded as transmitting the virus of streak disease of maize in Natal, also belonged to this genus, and two new species C. arachidis and C. similis were described from the Gambia, where they were reported as injurious to ground-nut and suspected of transmitting the virus of the rosette disease of that plant. Since that time Dr. H. H. Storey of the Amani Research Station has been investigating the possibility of transmission of the streak virus of maize by C. zeae. In attempting to breed strains capable of transmission of the disease certain crosses were made which showed conclusively that he was dealing with two distinct species. These species he was able to separate on the colour pattern of the abdomen. Dr. Storey has now sent to me material of both these species and a study of the genitalia corroborates his finding. One, of course, proved to be C. zeae, the other is new and I therefore propose to dedicate it to the discoverer.

1. There are four species of Otiorrhynchus which commonly, in both the larval and the adult stage, cause damage to strawberry plants.

2. The morphology of the first larval instar of these species is discussed from the point of view of their determination.

3. It is shown that although the larvae in this stage are superficially very similar, there are considerable differences in the chaetotaxy of the head and also in the form of the labrum and the setae situated upon it.

4. Similarly there are variations in the position and size of the setae on the dorsum of both the thorax and abdomen.

5. A table is drawn up summarising all these characters in each of the four species.

6. A brief description of the present knowledge of the biology of these species is also given. It appears that although all of them are usually parthenogenetic, it is at present uncertain whether they can ever reproduce sexually, since the presence of males has as yet not been recorded.

7. These species usually have only one generation in the year, ovipositing in mid-summer and over-wintering as well developed larvae. In the case of O. sulcatus and O. ovatus, however, adults may emerge late in the summer and, having hibernated as adults, lay eggs in the early spring following.

There are in Britain three species of gall midges the larvae of which may be found in pea-pods: the pea midge (Contarinia pisi, Winn.), which is the most common and is sometimes a pest; Lestodiplosis pisi, Barnes, a predator on the former; and Clinodiplosis pisicola, sp. n., an inquiline. The larvae are readily distinguishable both by their colour and by the structure of their anal extremities (fig. 1).

The distribution of Rastrococcus spp. within mango trees (Mangifera indica) was studied at Bangalore, India. Population densities of R. invadens Williams, R. iceryoides (Green) and R. mangiferae (Green) were significantly higher on the abaxial leaf surface compared with the adaxial surface. Mealybug density was also higher from ground level up to 2 m compared with above 2 m. Significant variations in Rastrococcus spp. populations among trees and species composition per tree were observed. As populations built up on leaves, migration to other leaves occurred, more predominantly in R. mangiferae than in R. invadens. As the population of R. iceryoides increased on leaves, migration to twigs occurred.

A dual cytogenetic and molecular analysis was performed in four species of Cyclocepala (Coleoptera: Scarabaeidae: Dynastinae) from Lesser Antilles (Martinique, Dominica and Guadeloupe). Two species/sub-species, C. mafaffa grandis and C. insulicola, are endemic to Guadeloupe. They have their own non-polymorphic karyotype and a fairly homogeneous haplotype of the COI gene. C. melanocephala rubiginosa has a distinct karyotype. Its COI haplotype is homogeneous in Guadeloupe and heterogeneous in Martinique. Finally, C. tridentata has highly different karyotypes and haplotypes in the three islands. In Martinique, its karyotype, composed of metacentrics, is monomorphic while its haplotype is fairly heterogeneous. Both are close to those of other Cyclocephala and Dynastinae species, thus fairly ancestral. In Guadeloupe, its karyotype is highly polymorphic, with many acrocentrics, and its haplotype fairly homogeneous. Both are highly derived. In Dominica, both the karyotype and the haplotype represent intermediate stages between those of Martinique and Guadeloupe. We conclude that several independent colonization episodes have occurred, which excludes that C. insulicola is a vicariant form of C. tridentata in Guadeloupe. Both chromosome and COI gene polymorphisms clearly indicate a recent colonization with a northward direction for C. tridentata.

The purpose of this study was to investigate and compare root morpho-anatomical traits and physiological responses of susceptible (SP81–3250) and resistant (H. Kawandang) sugarcane genotypes exposed to the attack by nymphs of spittlebug Mahanarva fimbriolata (Stål) (Hemiptera: Cercopidae). Two experiments were conducted to compare the damage caused by spittlebug nymphs on fresh and dry biomass weight; lignin content in stalks; root anatomy; chlorophyll content; photosynthetic rate (A); carboxylation efficiency (A/Ci); stomatal conductance (gS) and transpiration rate (E) of these genotypes. SP81–3250 consistently obtained significantly higher damage scores than H. Kawandang in both experiments, confirming the previously observed level of resistance in each genotype. Attack by spittlebug nymphs had a much higher effect on both fresh and dry biomass weight, chlorophyll content, A, A/Ci, gs and E of SP81–3250, than that on H. Kawandang. Anatomical studies indicated the presence of aerenchyma tissue in the root cortex of SP81–3250, a feature which may facilitate penetration of the nymph's stylet into the vascular cylinder. In contrast, roots of H. Kawandang are characterized by having more dense and compact parenchyma cells. In addition, infested plants of this genotype contained an unidentified mucilaginous compound in the vascular cylinder of the roots. We conclude that resistance of H. Kawandang to spittlebug is related to the ability of this genotype to maintain normal chlorophyll content, as well as stomatal conductance and photosynthesis, thus, allowing for biomass accumulation under spittlebug attack, in contrast to SP81–3250. In addition, the presence of more compact and denser parenchymal cells, as well as that of an induced mucilaginous compound in the root's vascular cylinder, are likely to hinder host-feeding activity in nymphs, causing higher nymph mortality and therefore, reduced damage in plants of this genotype.

Mung bean is highly susceptible to insect attack during storage. Hermetic storage is an effective technique to control insect damage. This study investigated the potential of the hermetic SuperGrain bag (SGB) for controlling bruchids during storage. The dry samples were packed in SGB infested with adult bruchids (SGB-I), SGB natural field infested (SGB-N), woven polypropylene bags (WPP-I and WPP-N) and kept at room temperature for 180 days. Oxygen (O2) and carbon dioxide (CO2) concentrations were measured at 15 days intervals. Moisture content, infestation level, seed damage and weight loss were determined at 60 days intervals. Seed colour, hardness, crude protein and fat contents were analysed before and after storage. The O2 level decreased to 10.09%, whereas the CO2 level increased to 8.87% in both SGB-I and SGB-N treatments. The moisture content of mung bean was maintained as onset storage in both SGB-N and SGB-I treatments, whereas reduced in WPP-N (9.26% db) and WPP-I (9.21% db). In SGB treatments, no significant bruchids were detected, but they increased drastically in WPP-N (52 ± 9) and WPP-I (377 ± 14). Seed damage (2–3%) and weight loss (0.8–1.0%) were recorded in both SGB-N and SGB-I. Conversely, seed damage reached 26.67 and 54.17%, corresponding to weight losses of 12.33 and 20.82% in WPP-N and WPP-I, respectively. Seed colour, hardness, crude protein and fat contents in SGBs showed no significant changes than in the WPP bags. The study illustrated that the SGB is an efficient hermetic device in protecting mung beans against bruchids attacks compared to the WPP bags.

In the grounds of the Medical Research Institute at Yaba, near Lagos, some 200 yards north-east of the laboratories there is a swamp, roughly circular, its diameter being about 20 yards. Until the present year, since first coming under observation in 1908, it has been definitely a pond, formerly used for watering cattle; small in the dry season, it sometimes assumed the dimensions of a lake in the rainy season. While it was a pond it harboured at least three different kinds of fish, and except for a few Anopheline larvae on rare occasions it was not a suitable breeding-place for mosquitos owing to the activities of the fish.

During the past summer (1916) Mr. C. B. Williams has, on behalf of the Department of Agriculture, Trinidad, been engaged in investigating the natural enemies of Tomaspis and its allies, in the hopes of finding some effective means of controlling the froghopper, Tomaspis saccharina, Dist., which in recent years has caused considerable damage to the sugar plantations of Trinidad. With this object Mr. Williams has made collections of minute parasitic Hymenoptera in the Island and the adjacent mainland of British Guiana, and this material has from time to time been forwarded to me for study. Mr. Williams has from the first been fully alive to the importance of securing any specimens of the egg-destroying Paraphelinus, Perk., and I am glad to find species of this interesting genus in the gatherings from both Trinidad and British Guiana. The literature dealing with Paraphelinus is scattered and perhaps inaccessible to those to whom it is most likely to prove serviceable. I have therefore, in some introductory notes, recapitulated the main facts in the life-history and host attachment and added a bibliography to the present paper.

Length of body (one male), 2·3 mm.; length of wing, 1·6mm.; greatest breadth of wing, 0·5 to 0·6 mm. A large, dark brown species resembling C. nigripennis, C.I. & M.

While our knowledge of the effects of variation of the physical conditions of the environment upon mosquitos is, in some directions, fairly satisfactory, in the case of the effects of variation of temperature there is lamentably little known. So far as a fairly complete survey of the literature dealing with mosquitos has revealed, there is only one paper specifically dealing with this matter, by Macfie (1920), although incidental observations have been recorded by other workers. This present paper is an outcome of an attempt to fill, to a slight degree, this lacuna in our knowledge. The investigations were carried out while the writer was attached to the Department of Zoology at the University College of North Wales, Bangor, and he has to express his thanks to Dr. C. L. Walton, Adviser in Agricultural Zoology, Department of Agriculture, Bangor, for allowing him to carry out the experiments in the Agricultural Zoology Laboratory.

The larva of Stegomyia fasciata passes through four distinct phases after it emerges from the egg and before it pupates. Under circumstances favourable to growth these phases are passed through very rapidly and the whole larval stage may occupy less than a week. In one experiment ten larvae which had hatched from their eggs on 1st April between 12 noon and 2 p.m. were isolated singly in small glass tubes containing a three-days-old broth medium. All these larvae cast their first pelts on the second day (2nd April), their second pelts on the third day, and their third pelts on the fourth day. The fourth and last larval pelt was not cast simultaneously by all the larvae, perhaps because by this time the nutrient value of the medium in the different tubes had begun to vary to an appreciable degree. Two larvae cast the fourth pelt on the seventh day, one on the eighth day, three on the ninth, one on the tenth, and one on the thirteenth day, and two died in this phase. One pupa died, but all the others hatched on the second day after pupation. In this experiment therefore the larval stage lasted on the average nine days, the shortest time being under seven days, and the longest thirteen days.

Different phosphoglucomutase (PGM) allozymes exist in the three sibling species of theAe. mariae complex. These enzyme variants appear to bedetermined at homologous loci by three codominant alleles designated as PgmA, PgmB andPgmC. Some populations of Ae. zammitii (Theo.) and of Ae. mariae (Ed. & Et. Serg.) were found to be homozygous PgmA / PgmA and PgmB/PgmB, respectively. A laboratory population of Ae. phoeniciae (Coluzzi & Sabatini) was found to be polymorphic for the PgmBand the PgmC alleles, the latter being conspicuously more frequent. An electrophoretically marked PgmC strain of Ae. phoeniciae was easily obtained. This is expected to be useful in release experiments for the study of pre-copulatory isolating mechanisms between this and the other two siblings of the Ae. mariae complex.