Fig. 6.
SEM of the third stage larvae of Oestrus sp. The first segment (head) bears 2 ventrally curved hooks with pointed ends (A). Three thoracic rings, with 3 regular rows of single-ended caudally projected spines are seen (B). Two oral hooks (C) and 2 caudal swellings (D) are visible. T, thorax; A, abdomen.