Ommatidial Number of Females of European Culex pipiens pipiens

The number of ommatidia in the 4th to the 6th rows in compound eyes were examined with females of European Culex pipiens pipiens and those of Egyptian strain of Cx. p. molestus. Generally, females of European Cx. p. pipiens had 9 ommatidia, but some female~ had 8 ommatidia. Most females of Cx. p. molestus had 8 ommatidia, but some of them had 9 ommatidia. Thus, it will be possible to distinguish the females of European Cx. p, pipiens and those of Cx. p. molestus in level of population based on the difference of the ommatidial number. Bull. Sch. Allied Med Scni., Nagasaki Univ. 2 : 167-171, 1988 Key w()rds : Culex ptplens plptens ommatidral number compound eyes Introduction In Europe, the mosquito of Culex pipiens complex is composed of 2 members of Culex pipiens pipiens and Cx. p. molestus. The former exhibits anautogeny, eunogamy, and -diapause, but the latter shows autogeny, stenogamy, and the lack of diapause. I ) There is little difference in external morphology between Cx. p. pipiens and Cx. p. molestus of either sex. On the other hand, non-autogenous Cx. p. pallens, and autogenous Cx. p. molestus. which are members of the Culex pipiens complex, are found in Japan. The males of the two member can be morphological distinguished by their external geniteLlia 4 ) and also the females can be generally discriminated by number of ommatidia in compound eyes ; the females of Cx. p, molestus have about 8 ommatidia in the 4 th to 6 th rows, whereas Cx. p. paller~s ommatidia have about 9. 2 ) 3 ) In this study, we compared the females of the European strain of 1 Department of Medical Zoology, Nagasaki University School of Medicine 2 Department of General Education, the School of Allied Medical Sciences, Nagasaki University 3 Institute of Tropical Medicine, Nagasaki University