Horridge, George Adrian2019-08-130044-362xhttp://hdl.handle.net/1885/165021In each ommatidium Notonecta (Hemiptera) has eight retinula cells of two types in an asymmetrical pattern.4 pagesapplication/pdfen-AU© 1968 Springer-VerlagAsymmetrical PatternRetinula CellOmmatidium Notonecta (Hemiptera)A note on the number of retinula cells of Notonecta1968-0610.1007/BF00341119