KEY TO GENERA AND SPECIES OF BELOSTOMATIDAE OCCURRING IN SINGAPORE AND MALAYSIA

1. Very large species, body length exceeding 60 mm; body shape elongate-ovate and parallel-sided (Fig. 1), lateral margins of hemelytra straight; inner margins of eyes parallel...... Lethocerus indicus (Lepeletier & Serville)

– Smaller species, body length less than 20 mm; body shape more rounded, lateral margins of hemelytra outwardly arcuate (Fig. 2); inner margins of eyes convergent anteriorly.................. Diplonychus rusticus (Fabricius)