 Most of them infect the large intestine by oral ingestion of the larva.The superfamily consists of the Strongylidae (including the strongyles of equines), Chabertiidae (including the nodular worms), Syngamidae (including the gapeworms of birds) and Deletrocephalidae (of "Rhea americana").The gapeworms (Syngaminae) develop to the third larval stage inside the egg.