198 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 112 



While measurements of size (especially wing length) and various 

 body ratios have been utilized in species descriptions, in many in- 

 stances they are of little diagnostic value because of inadequacy of 

 sample size in the original description. For example, Townes (1945) 

 averaged only three measurements of each characteristic of each species. 

 While admitting its inadequacy from the standpoint of population 

 statistics, a compromise was effected here by measuring a minimum 

 of three specimens (where available) from each locality and date for 

 each species; thus both seasonal and geographic variations are in- 

 cluded. For each series of measurements the range is given, followed 

 by the mean with the number of specimens upon which the statistic 

 is based given in parenthesis. 



The nomenclature is essentially that used by Townes (1945) but 

 with some modifications as given by Freeman (1957, 1958) in his 

 recent monographic series on African midges. A summary of the 

 changes incorporated here is given by Dendy and Sublette (1959). 



This paper is based on four of the larger collections of California 

 Chironomidae. For making them available, I thank Dr. J. N. 

 Belkin, Department of Entomology, University of California, Los 

 Angeles; R. E. Darby, formerly a graduate student at the University 

 of California, Davis, now at the Life Sciences Department, Sacra- 

 mento State College, Sacramento, California; Dr. A. T. McClay, 

 University of California, Davis, and Dr. W. W. Wirth, U.S. De- 

 partment of Agriculture, Washington, D.C. 



The holo types and material collected by Dr. Wirth are deposited 

 in the U.S. National Museum. The deposition of specimens is in- 

 dicated in parenthesis immediately after locality and collector. The 

 names of the following collectors have been abbreviated in the text 

 as follows: Willis W. Wirth (W), R. E. Darby (D), J. N. Belkin (B) 

 and A. T. McClay (M). Location of the specimens is shown before 

 each entry; abbreviations are used for U.S. National Museum (USNM), 

 University of California (UC), and University of California at Los 

 Angeles (UCLA). All localities mentioned are in California. 



For her indispensable aid in preparing the genitalia mounts and for 

 her assistance in the preparation of the manuscript I should like to 

 thank my wife, Mary Smith Sublette. Appreciation is also due Dr. 

 Willis W. Wirth for reading the manuscript and making many helpful 

 suggestions. 



Pseudochironomusrichardsoni Malloch 



Pseudochironomus richardsoni Malloch, Bull. Illinois State Lab. Nat. Hist., vol. 

 10, p. 500, 1915. 



Males: Wing length, range 2.22-2.89; mean 2.55 mm. (8); leg 

 ratio, range 0.84-0.94; mean 0.88 (4); antennal ratio, range 1.74-2.62; 

 mean 2.21 (6). 



