Animal and plant enemies undoubtedly play an important part in controlling mosquitoes, but it is fully recognized that a study of these organisms forms only one phase of a very complex subject spoken of generally as natural control. Climate, weather conditions, topography, etc., all have an important bearing on mosquito abundance. Precipitation, whether in the form of rain or snow, and temperatures, exert a vital influence on mosquito populations. If the winter accumulation of snow is heavy, the spring infestation of snow pool and floodwater mosquitoes may be expected to be heavy too.

The following four species are very closely allied and in the adults possess no very definite characters for specific distinction, even the male genitalia failing in this respect. This leads me to believe that we are dealing with a group the individuals of which have split away either from each other or from a parent form at a comparatively recent date and that even now fresh species may be in the act of formation. The nymphs offer much better specific characters and, once recognized, are not readily confused; long series of bred material may result in the discovery of good adult characters but for the present I am basing my conception of the different species largely on nymphal distinctions.

In 1908 Professor T. D. A. Cockterell, (Trans. Am. Ent. Soc., xxxiv, 247-254) reviewed the American species of the Family Nemestrinidae occurring North of Mexico, including the fossil forms, and in that paper three species of the genus Rhynchocephalus were considered. During the summer of 1922 the author captured a number of specimens of a species of Nemestrinidae while on a collecting trip at Baldwin Hill, about 12 miles from Lawrence, Kansas.

Two mistakes have become so prevalent among entomological writers that it would seem to justify the following observations. I. The use of the word “punctuation” instead of “punctation”. There are few North American writers who have not made this mistake. Notable exceptions are Dr. LeConte, possibly because he generally wrote his descriptions in Latin, and Dr. Horn, who generally used the words “punctate” or “punctured”.

Differs from typical gordius from the cast in its smaller size and more constrasted maculation, the costa and inner margin of forewing being shaded with deep smoky whilst the central portion of the wing is suffused with whitish shades, especially preceding the wavy subterminal dark line. Between this line and the outer margin of the wing the teriminal area is heavily suffused with deep smoky, in contradistinction to gordius borealis Clark in which this region is sprinkled with whitish, more as in the typical form. The dark intravenular streaks are reduced, much as in gordius oslari R. & J. from Colorado, but from this race the smaller size and the better defined transverse lines will distinguish it. Expanse 70 mm.