Abstract: The genitalia of male Agrotis ypsilon Rott. Originated from the eighth abdominal segment is supported by 5 pairs of muscles. It has fully functional clasper and pleurite in the ninth abdominal segment. There are eight pairs of muscles in the genitalia. There are a pair of think nerve trunks named 9+10+11 rising as the lateral nerves of the ninth, tenth and eleventh primitive abdominal ganglions. The muscles of the male genitalia are innervated by the nerve branches of the nerve trunks.