Imperfect excision of the P{lacW.2Bbc-1} element, removing the 5' end of the transposon and at least 38kb of genomic sequences up to position 15000 or less on cosmid 25D2.
Lethality occurs during the third larval instar. The early ecdysone puffs 50CD, 74E, 75B and the late puffs 29F, 46F, 62E, 71CE, 78C, 82F, 85D, 93D and 98E are not present in mutant larvae. The intermolt puffs 34A, 25AB and 68C do not disappear in these mutants.