Journal of the Entomological Society of Southern Africa - Volume 9, Issue 1, March 1946

It may at times be felt that entomology is a most unsatisfactory science; there are altogether too many insects. Immediate qualification is needed; conditions are probably neither better nor worse than in zoology generally, or in botany, or in biological sciences generally. Comparison with such sciences as astronomy and geology may not convey very much that is worth while. All the same, if one wants an interesting and absorbing occupation, either as a profession or as a hobby or both as is the habit of some unfortunates, the study of insects, their lives, habits and classification, is one of the best. The amount of satisfaction obtained from such a study will depend partly on the nature of the subject, but mostly perhaps on the personality of the worker and on his temperament and outlook.

Nanothrips parviceps spec. nov. (Figs.* 1 -3). Female (apterous). Length 0.96 to 1.22 mm. (distended). Colour: Body brown, head, antennae, tube and most of legs yellow. Head yellow; antennae: i to vi wholly yellow, vii slightly brownish at apex, viii grey-brown. Thorax uniformly light brown; legs: all coxae and trochanters light brown; middle and hind femora pale yellowish brown in basal half; rest of legs yellow. Abdomen: i - ix like thorax; tube orange yellow, its distal one-sixth brown. All setae greyish-yellow.

In view of the increasing number of complaints from farmers that they were not able to control the Mediterranean fruit fly (Ceratitis capitata Wied.) satisfactorily in orchards in the Western Province, laboratory investigations commenced by Nel in 1940, were continued by the writer during the months March to June, 1945. The recent experiments were designed essentially to determine the concentrations of the newly developed toxicants, gammexane and DDT, which would be economically effective when ingested by this fruit fly. The present paper embodies some of the results of the preliminary experiments. The detailed investigation of the effectiveness of baits containing these toxicants exposed to various laboratory and outdoor conditions is proceeding.

It seems probable that Trimen overlooked these two species in specimens he must have examined from Natal. They are both superficially very like M. safitsa Hewitson, which is so common in all the coast bushes. I have good series of both the above species, which agree with the descriptionptions given by Aurivillius in Seitz, Macrolepidoptera, 13 : 94, and regard them as likely captures wherever Mycalesis fly.

Apanteles halfordi sp.n. Female Male. Black. Anterior femora above, hind femora and tarsi, and antennae, dark brown; middle femora, tibiae and tarsi, hind tibiae except at the extreme base and hypopygium, dark reddish-brown; anterior femora below, anterior tibiae and tarsi and base of the hind tibiae, red testaceous; hind coxae black; tegulae dark brown to black; palpi darkened; tibial spurs pale.

Some sixth stage hoppers of the Red Locust, Nomadacris septemfasciata Serville, were fed on the leaves of Oxalis purpurascens, and were used as subjects for respiration experiments in the micro-Haldane apparatus. Their respiratory quotient was invariably 1.3. This indicates that more oxygen is being liberated than would be required to metabolise the food, and thus it appears that fat metabolism may be very active. It was decided to carry out a special balance experiment with one animal while others were killed for the purpose of extracting and analysing their fat.

There are some physiologists, morphologists and other non-systematists who regard taxonomy as a branch of zoology that is beyond the pale of modern science, and quite unworthy of the attention of serious workers. Taxonomists very naturally resent this sort of attitude, and they have plenty of opportunities to smile when those who deprecate taxonomy nevertheless come ""hat in hand"" to ask the despised systematist for identifications of the material used in their ""truly scientific"" work.

The majority of the records contained in the following list of food-plants of South African Lepidoptera have already appeared in a number of papers in various publications, including the ""Entomologist's Record and Journal of Variation "", ""Journal of the Entomological Society of Southern Africa "", ""Farming in South Africa "", and departmental bulletins during the last twenty years. It was thought that it would serve a useful purpose to compile these records in one list and this has now been done. Several records, not hitherto published, have been included.

Plants have been used from time immemorial as a source of poisons for various purposes and in many tropical countries native lore has provided clues to insecticidal plants from which highly efficient insecticides have been developed. The toxins are, however, so combined chemically in the parent plant that various animals and insects may feed on the plant without coming to any harm. Although finely ground poison-bearing tissues of some plants are used as such, the toxic principles are usually extracted by means of an organic solvent before being put to use as insecticides.

Studies made on swarming locusts have shown that there is a number of morphological and developmental differences between hoppers reared in crowds and those reared in isolation. The most striking of these differences is found in the colour pattern, and it is most conspicuous in the final instar hoppers. The hopper reared in a dense crowd has a basic black background colour with orange-yellow markings. The adults are characterized by having longer wings and shorter or more compressed pronota. The isolated forms show a greater variation in the colour pattern of the hoppers, which varies from green to grey-blackish, but the black and orange pattern of the swarm type is never found. The adults of these solitary forms generally have relatively short wings and the pronotum, especially in Locusta migratoria, is larger and much more convex in the lateral aspect.

Many of the species of Acari recorded in this paper have been reported from a number of countries but in most cases are very imperfectly known from the Ethiopian region. Bedford (1, 2) who listed ectoparasites from South African domestic and wild animals paid relatively little attention to the Acari so that unfortunately our records in this country are very incomplete.

During the course of routine testing. of insecticides against locusts, DDT (dichlor diphenyl trichloroethane) and 666 (1,2,3,4,5, 6, - hexachlor-cyclohexane) were used in small scale laboratory experiments against the brown locust [Locustana pardalina (Walker)] and the migratory locust (Locusta migratoria migratorioides R. & F.). In view of the wide attention that these two insecticides have received of late, it was considered advisable to publish these preliminary results.