C. Jl Williams 245 



Summary. 



(1) Peas and beans in England and Western Europe are damaged 

 by a thrips Kakothrips rohuslus (sub-order Terebrantia, family Thripidae). 



(2) The adults appear from May to August; males only in the 

 earlier part. The eggs are laid chiefly in the tissue of the stamen 

 sheath. They hatch in about nine days. The larvae are orange- 

 yellow with the last two abdominal segments dark brown. There is 

 one moult. The second stage when full fed (about 24 days from the 

 laying of the egg) descends into the ground to a depth of from three 

 to twelve inches. 



(3) The full fed larva remains in this position till the following 

 spring when the two pupal stages are passed through and the adult 

 emerges. There is only one brood each year. 



(4) The damage is greatest on light soils. No varieties are immune, 

 but early sown plants are less damaged. A chalcid parasite, Thripoc- 

 tenus briii, has been recorded from France, but has not been found in 

 England. 



(5) Artificial control is difficult. Spraying is only of use when the 

 larvae are feeding openly on large pods. Soil fumigation during the 

 winter should give good results, but must be done to a sufficient depth. 



BIBLIOGRAPHY. 



Bagnall, R. S. (1908). Notes on Some Genera and Species of Thysanoptera new 



to the British Fauna. Ent. Mon. Mag. 2nd S., xix, p. 4. 

 (1914). A Chalcid Parasite of Thrips. Rept. Brit. Assn. Adv. Sci. 1913, 



London 1914, p. 531. 

 Board of Agriculture of England (1898, revised 1905). Pea and Bean Thrips, 



or Black Fly {Thrips pisivora). Leaflet 48. 

 BuFFA, P. (1907). Trevtuna Specie di Tisanolteri iialiani. Pisa, p. 60. 

 CoLLiNGE, W. E. (1906). Report on Injurious Insects, 1905, p. 12. 

 Gaumont, L. et VuiLLET, A. (1914). Sur un Thysanoptdre nuisible aux Pois. 



Bull. Soc. Nat. Agric. France, lxxtv, pp. 168-173. 

 Hood, J. D. (1912). A new Genus and three new Species of N. American Thysano- 

 ptera. Psyche, xix, p. 113. 

 HowLETT, F. M. (1914). A Trap for Thrips. Journ. Econ. Biol, ix, p. 21. 

 Karny, H. (1907). Die Orthopterenfauna des Kiistengebieles von Osterreich- 



Ungarn. Berlin. Ent. Zeit, lii, p. 45, footnote. 

 (1910). Neue Thysanoptera der Wienergegend. Mitteil Nalurw. Ver. Univ. 



Wien, VIII, p. 45, footnote. 



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