Nomic

NOMIC.

From the point of view of utility to man a few members of the order may be classed as beneficial. The most important are the scale insects, notably the lac insect (Ta chardia lacca) whose outer coverings yield the stick lac of com merce from which shellac is derived; the insect is native to India. The cochineal insect (Dactylopius coccus) belongs to the same family and the dyestuff, cochineal, is prepared from the dried females. Similarly the dye-stuff known as Kermes or "granum tinctorium" has been prepared from almost time immemorial from the dried females of another Coccid, viz., Kermes ilicis. Sev eral other Coccidae yield wax in sufficient quantities to have been used commercially in the East, while the outer pearly coverings of Margarodes are the so-called ground-pearls which are strung into necklaces in South Africa and the Bahamas.

Mention needs to be made of the predatory Capsid Cyrtorhinus mundulus which has been utilised for purposes of controlling the sugar-cane leafhopper in the Hawaiian islands. The insect was introduced into that territory from Queensland and Fiji by F. Muir in 192o and the experiment has since proved highly successful.

BIBLIOGRAPHY.-No

general comprehensive work on Hemiptera Bibliography.-No general comprehensive work on Hemiptera exists, but text-books are available dealing with the British species, and the most important of these are the following: E. Saunders, Hemiptera-Heteroptera of the British Isles (1892) ; J. Edwards, Hemiptera-Homoptera of the British Isles (1896) ; E. A. Butler, A Biology of the British Hemiptera-Heteroptera (1923) ; R. Newstead, British Coccidae (1901-03) and F. V. Theobald, British Aphides (Ash ford, Kent [1926-27] still in course of pub.).

For the North American Hemiptera a useful guide is W. E. Britton, The Hemiptera or Sucking Insects of Connecticut (Bull. 20 Conn. Geol. and Nat. Hist. Survey, 1923) and most of the species inhabiting that continent are listed by E. P. Van Duzee Catalogue of the Hemiptera of America (Univ. Calif. Tech. Bull., Agric. Exp. Station, 2, 1917). For the scale-insects consult A. D. MacGillivray, The Coccidae (Urbana, Ill., 1921) and for the aphides numerous bulletins by E. M. Patch, pub. by the Maine Agricul. Experiment Station, are important. The same experiment station has also issued useful bull. (248 and 2J4: 1916) on froghoppers and leafhoppers by H. G. Osborn.

Among other works dealing with Hemiptera E. E. Green, The Coccidae of Ceylon (1896-1922) is comprehensive and beautifully illus. and the Lac insect is described by A. D. Imms and N. C. Chatterjee (Indian Forest Memoirs, 3, 1915) . J. B. Buckton's British Aphidae (1875-1882) is now out of date, but useful for the coloured illus.; see also J. Davidson, Catalogue of British Aphididae (1925: bibl.) . For aquatic Hemiptera an account is given by L. C. Natural History of Aquatic Insects (1912) and by G. W. Kirkaldy, Guide to the Study of British Waterbugs (Entomologist, 1898-1906). For the Cicadas see W. L. Distant, Oriental Cicadidae (1889-92) and C. L. Marlatt, The Periodical Cicada (Bull. 71 U.S. Bureau of Entomol., 1907), while their sound-producing organs are described and figured by C. Carlet in Annales des Sciences Naturelles (ser. 6, vol. v. 1877) . (A. D. I.)