295 

 Leech and Chandler; Coleoptera 



phoromyces (on Hydrobius, Sperchopsis, Cymbio- 

 dyta, Knochnis); Hydrophilomyces (on Phaenono- 

 tum); Eusynaptomyc.es (on Hydro chard); Lim- 

 naiomyces (on Hydrochara). 

 Hydraenidae — Thripomyces (on Hydraena); Hydro- 

 philomyces, (on Ochthebius. II .digitalis has also 

 been placed in the genus Misgomyces.) 

 Dryopidae — Cantharomyces (on Pamus, Parygrus, 



Pelonomus); Helodiomyc.es (on Pamus). 

 Collecting. — Success in collecting water beetles 

 depends largely on knowing what habitats to probe. 

 Some data are given for each family, under "Habitat 

 and distribution"; there is a good general discussion 

 and much information on individual species in Young's 

 The Water Beetles of Florida (1954). 



With an ordinary kitchen sieve, most people can, 

 without even wetting their feet, obtain more beetles 

 in a couple of hours than they are able to prepare for 

 the cabinet in as many days. For general collecting 

 the following are adequate: 



1 strongly made kitchen sieve or soup-strainer, 

 6'/£ or 7 inches across, with about 17 wires to 

 the inch. 

 1 similar sieve with a finer mesh, for smaller 



beetles. 

 1 pair of forceps (and a second pair for emergen- 

 cies). Vials of 80 per cent alcohol. Three useful 

 sizes are 95x25 mm., 70x20 mm., and 55x15 mm., 

 the smallest being reserved for mated pairs of 

 beetles, or for very small species. 

 Vials, empty and clean, for bringing home live 



specimens. 

 A square of white canvas or rubberized cloth, about 



4x4 ft. 

 To work deep water, some form of long-handled 

 water net or small dredge is most helpful. In the 

 swifter parts of rivers and larger streams, a kitchen 

 sieve is too small; a copper-mesh window screen, 

 frame and all, may be used. 



It is best to mount the beetles within a day or two 

 after they have been collected. If they must be stored 

 in alcohol for long periods, the alcohol should be 

 changed after the first day or two, since the first lot 

 is diluted by water when the beetles are put in, and 

 dirtied by the grease dissolved out of them. Specimens 

 killed in an ethyl acetate jar should not be left in 

 more than twenty-four hours; they may be put directly 

 into fresh 70 per cent alcohol, or layered in cotton 

 and subsequently relaxed. 



The majority of water beetles prefer shallow water, 

 where they hide among aquatic plants and underwater 

 debris near the shore. In general, the more the water 

 is roiled by the collector the higher the percentage of 

 beetles present he will catch. The sieve is worked 

 back and forth just above the bottom, with a turn at 

 the end of each stroke to keep the contents in place, 

 a dozen or so strokes being made through the eddies 

 created. If not too much debris is present, the beetles 

 may be picked out of the net with tweezers and popped 

 into alcohol or into an ethyl acetate killing bottle 

 (Valentine, 1942). If the water contains masses of 

 dead leaves, silt, or algae, dump the contents of the 

 net onto the white sheet, preferably in bright sun- 



shine, and pick out the beetles as they leave the 

 pile. In lieu of a sheet, use a flat rock or bare sloping 

 ground. If there is no time for this, put the entire 

 contents of the sieve into a large tin or a waterproof 

 bag, and examine it at home or run it through a Berle ie 

 funnel. Water less than a foot deep usually gives the 

 best results, and mere puddles or wet marshy places 

 should not be overlooked. 



In running water, hold the sieve or window screen 

 against the bottom, at a slight downstream angle, and 

 turn over stones and the like, upstream from it, lotting 

 the current wash the dislodged insects onto the 

 netting. 



Following is an annotated list of some of the 

 habitats to search for water beetles. 



Lakes. — The open waters of large lakes are almost 

 barren of water beetles. Rocky shore lines may provide 

 Dytiscidae, Psephenidae, and Elmidae. Shallow weedy 

 inlets and narrow bays, protected from wave action, 

 are good for Hydrophilidae, and if the host plants are 

 present, Chrysomelidae and Curculionidae. Large 

 schools of Gyrinidae occur here, as on ponds and the 

 backwaters of rivers. 



Ponds. — Ponds are of various sizes, and it depends 

 on local naming whether a given body of water is a 

 pond or a lake. In general, shallow ponds in open 

 meadows, with abundant plant growth, have the greats 

 est number of beetles. Here all families except the 

 Amphizoidae, Ptilodactylidae, Dryopidae, and Elmidae 

 occur. Woodland ponds tend to have colder and more 

 acid water; they contain fewer beetles, but species 

 which may not be found elsewhere; here look for 

 Helodidae. Ecologically ponds grade insensibly into 

 the quiet backwaters of streams and rivers, and into 

 seepage areas. Most aquatic Chrysomelidae and 

 Curculionidae are pond or lake shore forms. 



Streams. — The smallest streams are hardly more 

 than seepage areas; their inhabitants are nocturnal 

 and best collected at night by flashlight. Large rapid 

 streams are ecologically like small rapid rivers. In 

 the backwaters and around the edges of pools, expect 

 Haliplidae, Dytiscidae, Gyrinidae, Hydrophilidae; on 

 and under stones in the faster water, even far out from 

 shore, Dryopidae, Elmidae, Psephenidae, Ptilodacty- 

 lidae; on waterlogged wood and accumulations of 

 leaves, Amphizoidae, Hydraenidae, Hydrophilidae, 

 Helodidae, Dryopidae, and Elmidae; in sand, stones 

 and silt along the shore, Hydrophilidae, Hydraenidae; 

 in algae, Haliplidae, Hydraenidae, and Hydroscaphidae. 



Rivers. — Rivers are essentially large streams, and 

 carry much the same fauna, though the actual species 

 may be different. 



Swamps. — Swamps are usually difficult places in 

 which to collect. They provide chiefly Hydrophilidae, 

 Chrysomelidae, and Curculionidae. 



Springs. — Cold-water springs usually contain Dytis- 

 cidae, Hydrophilidae, Gyrinidae, and Helodidae. Hot 

 springs may have Dytiscidae, Hydrophilidae, Hydrae- 

 nidae, Hydroscaphidae, and Elmidae. 



Tree holes. — Some species of Helodidae live in the 

 water which collects in holes in trees. 



Shorelines. — Many small forms, especially Hydrae- 

 nidae and Hydrophilidae, occur in the wet sand and 



