C. P.  Alexander, ?Chapter 22. Ptychopteridae?, in Manual of Nearctic Diptera, vol. 1, J. F.  McAlpine, Peterson, B. V., Shewell, G. E., Teskey, H. J., Vockeroth, J. R., and Wood, D. M., Eds. Ottawa: Research Branch, Agriculture Canada, 1981, pp. 325-328.