Pyrethroid type insecticides described having the formula: ##STR1## wherein A=CF.sub.3 -C.dbd.C-, ##STR2## (X=H, F, Cl, Br: Y=Cl, Br) ##STR3## (group ##STR4## is bound to the hererocyclic ring in position 2 or 3) ##STR5## --CH.sub.2 --C.tbd.C--CH.sub.2 --R.sup.9 ; wherein:R.sup.1 =H, CN, C.tbd.CHR.sup.2 =3-phenoxy, 3-benzyl, 4-allyl, 4-propargyl.R.sup.3 =H, alkyl bound to the heterocyclic ring in position 3 or 2;R.sup.4 =(in position 4 or 5 of the heterocyclic ring)=benzyl, benzoyl, phenoxy, allyl, propargyl;Y=O, SR.sup.5 and R.sup.6 =alkyl C.sub.1 -C.sub.3, or R.sup.5 and R.sup.6 together form an orthocondensed aromatic, heteroaromatic or aliphatic, saturated or unsaturated ring;R.sup.7 and R.sup.8 (equal to or different from each other)=H, halogen, CH.sub.3 ; R.sup.9 =phenyl, vinyl, vinyl substituted, phenoxy,Compounds of general formula I are endowed with a high insecticide and acaricide activity.