RES Handbook Vol 4 Part 3. Coleoptera. Hydradephaga

This might be described as an abstract of British Water Beetles published by the Ray Society in 1940 and 1950 as most of the Keys and Illustrations are from ,those two volumes, and I have to thank the Council of the Ray Society for allowing me to use them. I have corrected several mistakes that occurred in those volumes and hope that I have not made any more! Not all the keys are identical with the earlier ones and that to Hydroporius is entirely new and, I hope, an improvement.