▁board ▁of ▁the ▁Micro le pid optera ▁Pala ear ct ica , ▁and ▁was ▁writing ▁the ▁Cole op hor idae ▁section , ▁a ▁volume ▁with ▁ 1 5 0 0 ▁pages ▁and ▁ 5 0 0 0 ▁draw ings . ▁He ▁had ▁nearly ▁finished ▁this ▁mon ograph ▁in ▁ 1 9 6 1 ▁when ▁he ▁developed ▁append ic itis , ▁and ▁died ▁of ▁heart ▁failure ▁soon ▁after ▁surg ery . ▁ ▁Research ▁T oll ' s ▁research ▁was ▁mainly ▁concentr ated ▁on ▁the ▁smaller ▁moth s ▁of ▁the ▁Micro le pid optera ▁group , ▁special ising ▁from ▁ 1 9 2 9 ▁on ▁the ▁T ort ric idae ▁and ▁Ne pt icul idae ▁families , ▁and ▁from ▁ 1 9 3 9 ▁on wards , ▁on ▁the ▁Cole op hor idae ▁family , ▁on ▁which ▁he ▁was ▁still ▁working ▁when ▁he ▁died . ▁He ▁re ared ▁many ▁c ater p ill ars ▁at ▁home , ▁and ▁worked ▁out ▁the ▁life ▁cycle ▁of ▁a ▁number ▁of ▁species . ▁He ▁accum ulated ▁a ▁large ▁collection ▁of ▁insect s , ▁and ▁don ated ▁about ▁ 4 0 , 0 0 0 ▁spec im ens ▁to ▁the ▁Municipal ▁Museum ▁at ▁Rost ov . ▁About ▁ 1 0 0 , 0 0 0 ▁spec im ens ▁were ▁given ▁to ▁the ▁ ▁of ▁the ▁Polish ▁Academy ▁of ▁Sciences . ▁He ▁also ▁collected ▁about ▁ 8 , 0 0 0 ▁bird ▁eggs ▁and ▁ 1 2 , 0 0 0 ▁but ter f lies ▁and ▁moth s ▁during ▁his ▁time