Two sphingophospholipids, sphingomyelin (ceramide phosphorylcholine), and ceramide phosphorylethanolamine, were isolated and purified from cells of four mosquito species obtained from the logarithmic and stationary phases of growth. Quantitation of the two lipids in both phases of growth from cells of each species was made. The fatty acid composition of the two lipids was compared between the cell types and the two phases of growth. There was a tendency for an increase of ceramide phosphorylcholine and a decrease of ceramide phosphorylethanolamine in the stationary phase. Longer chain fatty acids of ceramide phosphorylcholine were observed in the stationary phase than in the logarithmic phase of growth of the mosquito cells. The four species had distinctly different fatty acid patterns in the two complex lipids which might be useful for taxonomic purposes and cell identification.