Introduction 



tract general attention, and we would make long journeys to see 

 them. Fortunately, however, this marvel can be seen at home by 

 any one that has eyes and will look. 



While the web-building spiders are those that most often 

 attract attention, there are many that differ greatly from these 

 in habits; and the stratagems employed by these to escape their 

 enemies and to obtain their prey, in many cases, are scarcely 

 less wonderful than those of the web-building species. In a 

 word, the abundance of spiders, the great variations in the habits 

 of the different species, and the high development of instinctive 

 powers of many of them, render them exceedingly available for 

 purposes of study of animal behaviour, whether this study be pur- 

 sued by the lover of nature for his own enjoyment or by the teacher 

 who wishes to use it as a means of interesting young people in 

 the world about us and in training their powers of observation. 



The structure of spiders also offers attractive fields for study. 

 This is especially true if attention be given to the correlation 

 of structure and habits. As we find here the most elaborate 

 spinning habits, so too we find here the most complicated organs 

 for the production and manipulation of the silk which is spun. 

 Some spiders are sedentary, either trapping their prey by snares 

 or lying in ambush for it; others, like wolves, stalk their prey; 

 some make use of any retreat that they find; while others dig 

 tunnels in the earth; of the burrowing species, some merely 

 strengthen the walls of their burrow with silk, leaving the entrance 

 a simple opening into the earth; some build a watch-tower or 

 turret about the entrance; and some close the entrance with a 

 cunningly constructed hinged door. In each case the structure 

 of the spider is specialized in a way that adapts it to its peculiar 

 mode of life. 



Many of these correlations can be readily seen by the com- 

 paratively untrained observer. The short and stout legs of the 

 jumping spiders, the longer and more slender legs of the running 

 species, the extra claw on each foot of those that cling to webs, 

 the rakes of the chelicerae or jaws of the burrowing tarantulas, 

 the pearly lustre of the "night-eyes" of those that live in dark 

 places, and the protective colours of many species are all easily 

 observed adaptations to peculiar modes of life. And for the 

 trained observers many problems in the morphology of these 

 animals await solution. 



xiv 



