 The English mycologist John <unk> reported that Amanita muscaria was used for getting rid of bugs in England and Sweden , and bug agaric was an old alternate name for the species . French mycologist Pierre <unk> reported having tried without success to replicate its fly @-@ killing properties in his work <unk> des <unk> <unk> et <unk> de la France ( 1784 ) , and proposed a new binomial name Agaricus pseudo @-@ <unk> because of this . One compound isolated from the fungus is 1 @,@ 3 @-@ <unk> ( 1 @,@ 3 @-@ Di ( <unk> @-@ 9 @-@ <unk> ) <unk> ) , which attracts insects . It has been <unk> that the flies intentionally seek out the fly agaric for its <unk> properties . An alternative derivation proposes that the term <unk> refers not to insects as such but rather the <unk> resulting from consumption of the fungus . This is based on the medieval belief that flies could enter a person 's head and cause mental illness . Several regional names appear to be linked with this <unk> , meaning the " mad " or " fool 's " version of the highly regarded edible mushroom Amanita caesarea . Hence there is <unk> <unk> " mad <unk> " in Catalan , <unk> <unk> from Toulouse , <unk> <unk> from the <unk> department in Southern France , <unk> <unk> from <unk> in Italy . A local dialect name in <unk> in Switzerland is <unk> de <unk> , which translates as " Devil 's hat " . 
