Using cow-baited net traps in the coastal and hilly areas of northern peninsular Malaysia, 21 species of Anopheles mosquitoes were found. The distribution of common Anopheles is presented. The composition of the anopheline mosquito fauna was more diversified in the coastal areas than in the hilly areas. The displacement of Anopheles sundaicus by Anopheles subpictus and the disappearance of Anopheles hackeri in the coastal area were noted.
Antennal sensilla were first investigated in the eight medically and veterinary important Anopheles mosquito species (Anopheles argyropus, Anopheles crawfordi, Anopheles nigerrimus, Anopheles nitidus, Anopheles paraliae (= Anopheles lesteri), Anopheles peditaeniatus, Anopheles pursati, and Anopheles sinensis) of the Hyrcanus Group in Thailand, using scanning electron microscopy (SEM). Four types of sensilla, including sensilla chaetica (large and small), sensilla trichodea (sharp- and blunt-tipped), sensilla basiconica or grooved pegs (types I, II, and III), and sensilla coeloconica (large and small), were observed on the female antennae of the eight species. The greatest number of sensilla found along the flagellum of all the Anopheles species consisted of sensilla trichodea. Grooved pegs type II were not found on the antennae of An. peditaeniatus. Interestingly, clusters of 10-15 grooved pegs type III, with blunt-tipped and unevenly grooved-lengthwise sensilla, and a sunken group of 7-12 grooved pegs type III, with slightly curved and point-tipped sensilla, were found distally on flagellomeres 3-7 of An. argyropus and An. peditaeniatus, respectively. In addition, the key for species identification, based on fine structure and morphometrics of antennal sensilla among the eight species, was constructed and differentiated successfully. However, in order to focus intensively on the exact function of these sensilla, further electrophysiological study is needed in understanding their significant role in mosquito behavior, especially when these insects seek hosts for transmitting pathogens to humans.
Facts are presented which suggest that mosquitoes of the Anopheles barbirostris species group that gave me a very uncomfortable night in 1941, whilst serving with the Volunteer forces, were probably A. donaldi. This species is now known to be a vector of human filariasis and probably malaria. Some of the steps are described by which I was led, sixteen years later, to recognise and later name donaldi as a new species. Reasons are given for thinking that around 1918 A. donaldi was present in some numbers at the railway town of Gemas where malaria was a serious problem. H.P. Hacker made a survey at Gemas in 1918 and though the principal vector was probably A. maculatus, 'umbrosus' and 'barbirostris' were the commonest larvae he found.