Published online by Cambridge University Press: 14 April 2009
The recovery of two EMS induced mutations which are dominant suppressors of the lethality of cryptocephal in Drosophila melanogaster are described. One of these mutations Su(crc)1 is described in detail. It maps very close to cryptocephal at 54·7 on the second chromosome and its suppression of cryptocephal is temperature-sensitive. Temperature shift experiments show that the temperature-sensitive period is from before the pupariation until 12 h post pupariation. The temperature-sensitive period of Su(crc)1 is discussed in relation to the expression of l(2)crc, head eversion and the timing of pupal chitin synthesis.