Molophilus is a cranefly genus within the Eriopterini tribe, with relatively small larvae that lack the swollen tail segments of other Eriopterini. Like other tipulids the general body form is worm-like, with the head retracted into the body. The spiracular disc (breathing apparatus at the tip of the tail) is surrounded by 5 short rounded lobes, each with dark pigmentation.
Molophilus larvae are found in small proportions of stream samples, but they are found in bush covered and farmland streams.
New Zealand studies have shown they feed on plant detritus and a range of streambed algae.
Molophilus larvae are among many taxa that are not strongly associated with particularly good or bad water quality. They have mid-range tolerance values of 5 (hard bottom sites) and 6.3 (soft bottom sites).