Laboratory experiments with the last 2 instars and tadpole dummies and their statistical analysis showed 2 initial phases in the predatory behaviour, viz. (1) prey detection, which was measured and expressed as reactive distances (RD: distance at which larvae respond to prey by head movements); and – (2) pursuit of the prey, which is expressed as "critical distance” (CD: distance at which larvae leave their resting position by propulsive reaction). — RD (frontal presentation of dummies) showed a significantly positive correlation with prey size. CD was lower than RD and increased only slightly (but also significantly) with increasing dummy length.