Definition that contains parasitically
- spiny-headed worm any of various worms living parasitically in intestines of vertebrates having a retractile proboscis covered with many hooked spines
- tachina fly bristly fly whose larvae live parasitically in caterpillars and other insects; important in control of noxious insects
- acanthocephalan any of various worms living parasitically in intestines of vertebrates having a retractile proboscis covered with many hooked spines