none Aphidius rhopalosiphi; WEIGHT-; SILK-; Mummies of diapausing vs non diapausing larvae; DIAPAUSE-; Diapausing vs non diapausing larval mummies; HEMIPTERAN-HOSTS; Sitobion avenae; Mummies of diapausing vs non diapausing parasite larvae, morphometrics; COCOONS-; Mummies containing diapausing vs non diapausing larvae; Morphometric comparisons Sitobion avenae; HYMENOPTERAN-PARASITES; Aphidius rhopalosiphi; Mummies of diapausing vs non diapausing parasite larvae, comparisons The morphology and ultrastructure of aphid mummies formed by diapausing and non-diapausing larvae of Aphidius rhopalosiphi De Stefani Perez, are described. Two types of silk thread were present in both types of cocoons: well-structured rounded threads, and flat threads which form a gum coating. Differences in the cocoon weight were observed depending on parasitoid development. A morphometric characterization of the two groups of mummies is given.