Three for the price of ...

Three for the price of ...

Observation - Three for the price of .... Description: Water Scorpion, Great Diving Beetle and a marshland 'water-walking' spider (quite large, up to 10mm), what is the latter species?

Water Scorpion, Great Diving Beetle and a marshland 'water-walking' spider (quite large, up to 10mm), what is the latter species?