SPIDERS 39 



from the spinnerets. The force of the leap draws out the thread, 

 and thus the spider swings back again on to the perpendicular 

 face of the wall and is saved from falling headlong to the ground. 

 Other spiders, especially members of the family Thomisidcz, conceal 

 themselves among flowers, particularly on plants whose blossoms 

 are closely clustered together as is the case in dead-nettle, mignon- 

 ette, composites of all kinds, orchids and others ; and there lie 

 in waiting for any insect that may chance to visit the flowers 

 in search of nectar or pollen. Many of the spiders which exhibit 

 this habit are of the same colour as the blossoms among which 

 they lurk, and are thus very perfectly concealed. For example, 

 the spider found among the dead-nettle flowers is white, that 

 among the mignonette green ; while the curiously shaped Thom- 

 isus abbreviatus, frequenting pink orchids and heather and also 

 yellow flowers, is sometimes pink and sometimes yellow, and 

 generally, though not invariably, is found to select flowers of the 

 same colour as itself. 



A remarkable fact, and one that has not yet been fully worked 

 out, but would well repay careful study, is the manner in which 

 the darker and lighter tints of colour are arranged upon the 

 bodies of spiders. A very common scheme of colour among all 

 animals is the disposal of darker shades upon the upper surface 

 which receives the strongest light, and of the paler tints upon 

 the lower surface which is naturally in the shadow cast by the 

 body itself. The effect of this arrangement is to neutralise the 

 high lights above and also the cast shadows beneath, and thus 

 to lessen or completely do away with the bold relief in which 

 the animal would otherwise stand out. Now, many spiders spin 

 more or less horizontal webs, and rest upon the under surface 

 of the snare in an inverted position. Hence it is the ventral 

 side of such spiders that receives the strongest light, and the 

 dorsal that is in the deepest shade. It is thus most interesting 

 to find here a reversal of the common colour scheme, the ventral 

 surface being the darker and the dorsal the paler. 



A singular method of seizing the prey is found in the rather 

 scarce spider Atypus piceus. This animal forms a silken tube 

 in a deep cylindrical hole excavated by itself in the earth, and 

 generally on the projecting ledge of a bank covered with some 



