Overexpression of Src64B^hs.2sev by heat shock at 37^oC for 1 hour every other day during development is lethal. Over 85% of embryos carrying two copies of Src64B^hs.2sev show abnormalities when Src64B^hs.2sev is expressed using a 30 minute heat shock at 37^oC between 5 and 8 hours of development. These include failure to undergo germ band retraction and grossly abnormal nervous system morphology. Expression of Src64B^hs.2sev in adults causes roughening of the eye. The regular array of the ommatidia is grossly distorted. Over half the ommatidia contain an excess of photoreceptor cells with small rhabdomeres.