8 HETEROPTERA OF EASTERN NORTH AMERICA. 



minor forms I consider the third name to represent. The 

 name of the typical variety, if more than one exists, is not 

 printed as a trinomial. I thus use Eustictus tristigmus (Say), 

 not Eustictus tristigmus tristigmus (Say), In many cases I have 

 not recognized the so-called geographical races or color vari- 

 eties of recent authors. Where a well known species ranges 

 over a large area, the different environments due to altitude, 

 variation in mean annual temperature, atmospheric conditions, 

 difference in topography, drainage and soils, varied food plants 

 and many other causes, are sure to bring about certain changes 

 in its color or external structure. If only the extremes of 

 these variants be at hand they are often so different in appear- 

 ance as to cause them to be considered races or even different 

 species. However, where a large series from all parts of the 

 range are present, intermediates are almost sure to be found 

 and there is little use and often much resulting confusion in 

 giving or recognizing a name for each slightly variable form. 

 A geographical race, or even a species may be wholly based on 

 color characters alone, provided those characters are fairly 

 constant, as in the fixed color of an antennal joint or the pres- 

 ence of a cross-bar on pronotum or elytra, but to name numer- 

 ous color varieties based upon the variation of the amount of 

 fuscous or red of the pronotum or elytra, as has been done in 

 Paracalocoris and other genera, is nonsense. One might as well 

 give to each spotted dog a varietal scientific name. 7 



Bibliography. — The bibliography near the end of this vol- 

 ume is not a complete list of the works pertaining to the Het- 

 eroptera of Eastern North America, but contains only the 

 names of those works to which especial reference has been 

 made in the text, and a few additional ones which it was 

 thought might at times be of use to the student of our fauna. 

 In the bibliography the list of papers is arranged alphabetical- 

 ly by authors and each author's works chronologically by 

 years. Where more than one paper by the same author ap- 

 peared in any one year the letters a, b, c, etc., follow the year. 

 Thus a citation in the text to Van Duzee (1916b, 100) will 

 be found, by reference to the bibliography, to refer to page' 

 100 of his paper entitled "Monograph of the North American 

 Species of Orthotylus," published in the Proceedings of the 

 California Academy of Sciences, Vol. VI, No. 5, pp. 87-128. 

 After the name of each family, subfamily, genus and species 



7 See Journ. N. Y. Entom. Soc. XXXII, 1!<24. p, 150. 



