drain fly
... that larvae of the drain fly can be found in trickling filter systems used to process sewage?
... that larvae of the <b id="mwBLw"><a href="./Psychoda_alternata" id="mwBL0" rel="mw:WikiLink" title="Psychoda alternata">drain fly</a></b> can be found in <a href="./Trickling_filter" id="mwBL4" rel="mw:WikiLink" title="Trickling filter">trickling filter</a> systems used to process sewage?