author(s)
A Vasudha, Md. Abbas Ahmad and ML Agarwal

abstract
Experimental studies on life history traits and immature stages of pumpkin fruit fly, Zeugodacus (Zeugodacus) tau (Walker) revealed that the pre-oviposition and incubation periods were 11-13 days and 1.21 ± 0.06 days, respectively. Per cent hatchability of eggs was 80.0 ± 7.07 per cent. The average duration of larvae was 6.60 ± 0.15 days and larval survival was 75.00 ± 11.18 per cent. The average pupal duration was 7.45 ± 0.23 days and the percentage of adult emergence from pupae was 70.00 ± 7.07 per cent. Sex ratio (male: female) was 1:1.27 and life-cycle was completed in 15.26 ± 0.23 days. The freshly laid eggs were elliptical, glistening white measuring 1.3-1.4 mm long and 0.22-0.24 mm wide. The three larval instars measured 1.8-3.0, 3.8-7.0 and 7.8-9.0 mm, respectively. Pupa was exarate, 4.9-5.5 mm long, brownish or reddish-brown, with free appendages, encapsulated within a puparium. Illustrations for various life stages of Z. tau have been included.