Cephus cinctus

Cephus cinctus, also known as wheat stem sawfly, is a slow flying, yellow and black colored, destructive pest found mainly in western North America. The adult fly grows to a length of 7 to 12 mm. Males are considerably smaller than females. However, they are delicate and short lived. The species has a wide host range that includes all large-stemmed grasses except oats, Avena sativa L. It is known as a chronic pest in Northern Great Plains of the United States and also an important pest of wheat in the Canadian Prairies. The species is distributed widely in various regions of the USA and Canada.

(Text from Wikipedia, the free encyclopedia.)