The photo shows an abnormal pattern formation in Drosophila (fruitfly). Mutations in homeotic genes cause abnormal placement of structures in an animal, such as the legs extending from the mutant fly’s head in place of antenna.
Urry, Lisa A.. Campbell Biology. Pearson Education. Kindle Edition. https://www.pearson.com/us/higher-education/series/Campbell-Biology-Series/2244849.html