PREFACE. 



WITH profound satisfaction the author gives to the scientific public the 

 third and last volume of a work which has engaged his thoughts for more 

 than twenty years. That he has been permitted to finish a labor 

 prolonged throughout so great a period, and wrought upon 

 amidst the many duties and burdens of a busy professional career, 

 excites earnest gratitude. The fear that he might not finish his self im- 

 posed task, and thus leave an incomplete work, has caused sore anxiety, 

 especially when, at sundry times, more or less serious illness has commanded 

 pause. Happily this apprehension is now dismissed, and the duty at last 

 ended is herewith submitted to the judgment of fellow workers in and 

 lovers of Natural History. 



In the first part of the volume six chapters are taken to consider various 

 natural habits and physiological problems for which there was no space in 

 the two previous volumes. These topics are in the line of those 

 studies in (Ecology to which the author has heretofore especially 

 ^ , given his attention. In addition thereto, and forming indeed the 



bulk of this volume, the second part thereof contains descriptions 

 of many indigenous species of Orbweavers, illustrated by thirty litho- 

 graphic plates, colored by hand from Nature. Most of these plates are 

 of Orbweavers, the group to which the author has given special syste- 

 matic study. But two plates are added, without descriptions attached 

 thereto, of representative species of the other aranead groups, especially of 

 those species whose habits have been presented in the foregoing volumes. 

 This descriptive work has been thought necessary to complete studies 

 which avowedly chiefly concerned habits and industry. The general forms, 

 colors, and proportions of spiders as they present themselves to an obser- 

 ver's eye in Nature are important to the accurate understanding of their 

 habits. One cannot appreciate in full the role which these creatures hav.c 

 to play in Nature until he have a just conception of how they look in 

 the midst of the scenes wherein their life energies are spent. For this 

 reason it formed part of the author's original purpose to present the sub- 

 jects of his study as they appear in natural site, that his readers may have 

 acquaintance not only with their life history but with themselves. 



Moreover, in studying the habits of spiders it has been necessary to 

 identify the species, and in many cases to describe them. It has seemed 



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