Berry, R.E. 1998. <URL:>. Accessed 21 March 2012.

Eaton, Eric R, Kaufman, Kenn. 2007. Kaufman field guide to insects of North America. New York: Hillstar Editions L.C.

Flint, M.L. 2012. <URL:>. Accessed 21 March 2012.

Hickman, Cleveland P. Eisenhour, David J. Keen, Susan L. Larson, Allan. Roberts, Larry S. 2009. Animal Diversity New York, McGraw Hill. 

Iowa State University Entomology. 2012. Bug Guide. <URL:> Accessed 4 April 2012.

Marshall, Stephen A. 2006. Insects: Their Natural History and Diversity. New York: Firefly Boots Ltd.

Microscopy U.K. 2007 All about Hover Flies.  <URL: > Accessed 3 April 2012.

McGavin, G.C. 2002. Insects spiders and other terrestrial arthropods. Dorling Kindersly Inc, New York, U.S.A.

Skevington, Dr. J.H. 2011 Canadian national collection of insects, arachnids and nematodes. <URL:> Accessed 4 April 2012.

Swan, Lester A, Charles, Papp S. 1972. The common insects of North America. New York: Harper & Row.

Williston, Samuel W. M.D., Ph. D. 1886. Synopsis of the North American Syrphidae. Bulletin of the United States National Museum. Government Printing Office, Washington D.C.