EN
The effects of organo-phosphorus insecticides: malathion, dichlorvos, and trichlorfon on three days old house fly larvae were examined. Larvae were placed in glass dishes on cotton scraps impregnated with alcohol solutions of insecticides. Control tests were carried on scraps well impregnated with ethyl alcohol. Tests were performed at 30° ± 1 °C and 65 ± 5% humidity. The process of pupation was observed. 'I'his process was delayed by 24 hours at treated larvae in comparison to control ones. From 807 puparia derived from treated larvae - 46,4% showed morphological deformations. Deformed puparia were found on all examined concentrations of trichlorfon, dichlorvos and malathion. Puparia's deformations were at various degree: puparia generally correct but with characteristic convexlid, larviform puparia distinctly segmented, and larviform puparia with visible mandibular crooks. The deformed puparia did not differ in colour from control ones, but in some of them the characteristic lustre of incrustated cuticle was lacking. The deformated pupae showed weight decreases from 17-14 mg depending the insecticides concentration in comparison to control ones (23.5 mg).