Some observations on a newly recorded mermithid parasite of Ixodes ricinus L. [Acarina, Ixodidae]

This is the first record of a mermithid (Nematoda, Mermithidae) parasitic in body cavity of Ixodes ricinus adults collected at two localities in Denmark during 1993-1995. Out of 213 adults 13 were parasitized (females 8.1% and males 3.4%). Up to three mermithid larvae were observed per host. The juvenile mermithids were up to 20 mm long and from their mouth emerged a stylet 70 µm long. The morphology and ultrastructure of the mermithid juveniles was studied with scanning and transmission electron microscopes.