Inviable Hybrid Male Fruit Fly (IMAGE) University of Utah Caption This is a microscope image of the small male larval brain of a hybrid of two fruit fly species. Cell division stops, so male hybrid larvae die during the transition to the pupal stage and never become adults. Credit Aida de la Cruz, Fred Hutchinson Cancer Research Center Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.