VI PREFACE. 



which could he spared from the husy profession of teaching, to 

 the observation of their habits, and to the collection, description 

 and representation of the various species. 



After publishing a few short papers in Silliman's Journal, 

 and in the Journal of the Philadelphia Academy of Arts and 

 Sciences, he brought together his extensive series of notes and 

 paintings and offered them to the Boston Society of Natural 

 History for publication in its Journal. 



The Society readily undertook the publication of such a val- 

 uable contribution to American Natural History, but the cost 

 of illustrating such a number of forms rendered it necessary to 

 extend its publication over a long series of years. Thus, as I 

 understand from his son, Hentz never revised or even saw but 

 the first one or two parts of his work. In the course of publica- 

 tion a number of drawings, illustrating details of structure for 

 the most part, as well as a few notes, were set aside, probably 

 to lessen, as far as possible, the expense. This material was, 

 however, later collected by the former Secretary of the Society, 

 Mr. S. H. Scudder, and published, in the form of a supplement 

 to Hentz's monograph, in its ' Proceedings.' 



As many parts of this work have been long out of print, 

 the Council of the Society has determined to republish in a 

 connected form all of Hentz's arachnological writings, and thus 

 to prepare the foundation necessary for future work in a field in 

 which as little progress since, as before, Hentz's time has been 

 made. To render the work as valuable as possible, Mr. J. H. 

 Emerton, who has paid much attention to the study of our 

 native spiders, has added a very considerable number of notes, 

 descriptions and synonymical I'emarks, which will prove of great 

 assistance to the student. Two new plates from his skillful 



