[2] In Australia its distribution corresponds closely with the tropical and humid subtropical climate zones, including coastal and subcoastal Queensland and New South Wales as well as much of the Northern Territory.

Lethocerus insulanus is a large insect and among the largest of the belostomatids, with adults typically reaching a length of 50–70 mm (2.0–2.8 in).

It is an ambush predator of fish, reptiles, frogs and aquatic invertebrates and spends most of its time motionless in the water column.

[3] The larger belostomatids are colloquially called "toe biters" throughout the parts of the world where they occur.

[3] As hemipteran insects do not possess biting mouthparts, this is not a true bite but involves the water bug piercing the subject's skin with its modified proboscis or rostrum and introducing a combination of salivary enzymes, including proteases and amylase, the usual function of which is to incapacitate and digest its prey.