The detailed life history of the lablab bug. Coptosoma cribraria Fabricius has been studied under laboratory conditions on field bean, Lablab purpureus var. lignosus Medikus. The studies revealed that the egges were laid on the apices of tender stems, base of flower buds and green pods. The incubation period was slightly short (6.10 days) during August while, it was longer  (7.2 days) during December. The egg measured 0.63 mm in length and 0.45 mm in width. The nymphal stage passed through five instars and lasted for 32 to 45 days during August -September and 36 to 45 days during December-January. The pre-oviposition period and the oviposition period  were 13.20 and 29.20 days, respectively. The female bug was larger (4.88 mm) than the male (3.37mm). The adult longevity of female was 42.50 days and males lived shorter(29.20 days.) The sex ratio of females to male was 1.09:1.0.