296 



Leech and Chandler: Coleoptera 



mud a few inches above the water's edge. They float 

 to the surface when this material is pushed into the 

 water and stirred up. They may also be taken at night 

 with the aid of a light. 



Seashore. — By splitting open cracks in the rocks 

 with hammer and chisel, in the intertidal zone of the 

 Pacific Coast, the collector can find examples of the 

 families Carabidae, Staphylinidae, Hydraenidae, 

 Melyridae, and Elacatidae. A species of the family 

 Limnichidae has been taken in the mud of tidal flats, 

 and in clumps of grasses submerged at high tide. 



Miscellaneous. — Many species of water beetles fly 

 well, and during the spring and fall dispersal flights 

 (usually in May and early September) large numbers 

 may be taken at lights. Where the evenings are suf- 

 ficiently warm, light collecting is profitable throughout 

 the summer. During the day the beetles sometimes 

 mistake the shiny tops of cars (see Duncan, 1927) or 

 the glass of greenhouses and building tops (Felt and 

 Chamberlain, 1935) for water, and land with a sound 

 like hail. Knaus (1909) reported an evening fall flight 

 of the big liydrophilus triangularis Say at McPherson, 

 Kansas; thousands of them fairly blackened the sky 

 and produced a buzzing and humming noise. Two non- 

 entomologists fired into them with a shotgun and 

 brought down a number. 



Mounting. — In general, beetles less than 6 mm. in 

 length should be mounted on triangular "points"; 

 colorless fingernail polish is a suitable adhesive. 

 Since many species of water beetles are identified 

 by the form of the genitalia (usually of males), it will 

 save hours of work if the organs are extruded, or 

 completely dissected out, as a regular procedure in 

 mounting. This virtually requires the use of a binoc- 

 ular steroscopic microscope. Specimens taken from 

 alcohol or ethyl acetate jars are relaxed enough. By 

 holding them upside down between forefinger and 

 thumb, and probing and prying a little with a pin 

 which has a tiny right-angled hook on the end, it 

 is not hard to extrude the genitalia. In most cases the 

 parts are then clearly visible, but if necessary they 

 may be dissected off and mounted on a point under the 

 insect, or in a tiny vial of glycerin; often they are not 

 bilaterally symmetrical, and not suited for mounting on 

 a microscope slide. 



The males of many species of water beetles have 

 one or more segments of the front and middle tarsi 

 dilated and clothed beneath with hairs which may be 

 simple, dilated apically, or formed into adhesion 

 discs. Others obviously differ from the females be- 

 cause of their curiously shaped tarsal claws, tibiae, 

 femora, trochanters, or antennae, bearded or tufted 

 areas on the ventral surface, modified abdominal 

 sternites, or dorsal sexual sculpture. In many cases 

 (unfortunately including a number of small forms), it 

 is necessary to dissect the beetle to be sure of its 

 sex. 



REFERENCES 



BENJAMIN, R. K. 



1952. Sex of host specificity and position specificity 

 of certain species of Laboulbenia on Bembidion 

 picipes. Amer. Jour. Bot., 39:125-131, 19 figs. 



Bull. Brooklyn Ent. Soc, 

 Coleoptera. 3ull. Brooklyn 



BOARDMAN, E. T. 



1939. Field guide to lower aquarium animals. Cranbrook 



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BODENHEIMER, F. 8. 



1951. Insects as human food, a chapter of the ecology 

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1930. A review of our present knowledge of the geo- 

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DARLINGTON, P. J., JR. 



1929. Notes on the structure and significance of Palaeo 

 gyrinus. Psyche, 36:216-219. 

 DUNCAN, D. K. 



1927. An unusual condition found in collecting water 



beetles in Arizona. 3ull. Brooklyn Ent. Soc, 22:143. 



FELT, E. P., and K. F. CHAMBERLAIN 



1935. The occurrence of insects at some height in the 

 air, especially on the roofs of high buildings. N.Y. 

 St. Mus. Cir. 17, 70 pp., 4 text figs. 

 HALL, M. C. 



1929. Arthropods as intermediate hosts of heminths. 

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HATCH, M. H. 



1926. Palaeocoleopterology. 

 21:137-144. 



1926. Tillyard on Permian 

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1927. A revision of fossil Gyrinidae. Bull. Brooklyn 

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HODGSON, E. S. 



1953. A study of chemoreception in aqueous and gas 

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194 7. Insects as human food. Proc Ent. Soc. Wash., 

 49:233-237. 

 HURST, W. D. 



1945. Predaceous diving beetles in Winnipeg's water 

 supply. Jour. Amer. Wat. Wks. Assoc, 37:1204-1206. 

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1951. Nematodes infesting water beetles. Ent. Mon. 

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KNAUS, W. 



1909. Gunning for bugs. Ent. News, 20:364. 

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1951. Revision de Lissorhoptrus LeConte y generos 

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 46 figs. 

 LA RIVERS, IRA 



1949. Entomic nematode literature from 1926 to 1946, 

 exclusive of medical and veterinary titles. Wasmann 

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 LUTZ, F. E. 



1930. Aquatic insect pets. Nat 

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MARTIN, A. C, and F. M. UHLER 

 1939. Food of game ducks in 

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1953. Hydrophilidae e Dytiscidae del Sud India con 

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 SABROSKY, C. W. 



1953. How many insects are there? System. Zool., 

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1896-1931. Contribution 

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