Abstract
Abortive development of the filarial larvae, Brugia malayi, in the thorax of the refractory mosquito against the parasite was examined by a histological method. Until 24hr after infection G-cell of almost all of the larvae found in the thorax completed first cell division, however many of the larvae showed an abnormal appearance of cuticle. Until 48hr after infection almost all the larvae showed unusual features of cuticle and in some specimens prolapse of the cells were observed. On the 5th day after infection pigmentation around cuticle was observed on many larvae. Pigmentation which is blackish-brown in color remained unchanged in the thorax until the 10th day. The cellular response by the host mosquitoes, which was seen on the encapsulated larvae in the abdominal haemocoel, was not observed in the thoracic muscles.
