Answer: gregarine

AnswerCrossword Clue
gregarineOf or relating to a group of microscopic, wormlike protozoans that are internal parasites of insects, annelids, and other invertebrates
gregarinea member of the Gregarinida, a group of parasitic insects, molluscs and crustaceans
gregarine(of movement) Slow and gliding, as seen in these protozoans