Raillietina require two different hosts for a complete life cycle. The definitive hosts are mostly wild and domestic birds, and sometimes humans. The intermediate hosts are insects, such as ants and beetles.[13] Mature eggs are released from the avian host through feaces by detaching the last gravid proglottid. The number of egg cell in each egg capsule is an identifying feature of each species. Eggs develop into larval forms called oncospheres, which are ingested by ants, and enters the alimentary canal, from where they migrates into the abdominal cavity of the insect and develops into mature cysticercoids. A cysticercoid is an inflated sphere with distinct rostellar hooks, and each species has characteristic number and size of the hooks, which correspond to those of adult worms.[14] Development of the juvenile stage in the intermediate host comprises 5 stages, namely (1) oncosphere stage, (2) lacuna stage, (3) cystic cavity stage, (4) scolex formation stage and (5) cysticercoid stage, which is the ultimate infective form.[9][9][15][16] When the insect with infective larvae is ingested by birds, the cysticercoid is released in host by the action of digestive juices. The rostellar hooks then become attached to the intestinal wall. New segments begin to form and within 3 weeks of ingestion of the host, a mature tapeworm develops. Therefore, the entire life-cycle can take 6 weeks for completion.[7]