76 PECKHAM. [Vol. 1, 



A species, then, may depend for its preservation upon 

 either active or passive means of protection, the passive means 

 often outvaluing the active. But whatever the means may be 

 — fierceness, inedibility, protective resemblance, or mimicry — 

 I would suggest that one test of its efficiency may be found in 

 the fertility of the species. 



DIRECT PROTECTION. 



Reseniblances to Vegetable and Inorganic Tilings. 

 As a general rule the forms and colors ofspiders are adapted 

 to render them inconspicuous in their natural homes. Bright 

 colored spiders, except where sexual selection has been at work, 

 either keep hidden away or are found upon flowers whose tints 

 harmonize with their own. This rule, while it has numerous 

 exceptions, is borne out by the great majority of cases. A good 

 illustration is found in the genus Uloborus, of which the mem- 

 bers bear a deceptive resemblance to small pieces of bark or to 

 such bits of rubbish as commonly become entangled in old, 

 deserted webs. The only species in our neighborhood is Uloborus 

 plumipes,which I have almost invariably found building in dead 

 branches, where its disguise is more effective than it would be 

 among fresh leaves. The spider is always found in the middle of 

 the web, with its legs extended in a line with the body. There 

 has been, in this species, a development along several lines, 

 resulting in a disguise of considerable complexity. Its form and 

 color make it like a scrap of bark, its body being truncated and 

 diversified with small humps, while its first legs are very 

 uneven, bearing heavy fringes of hair on the tibia and having the 

 terminal joints slender. Its color is a soft wood-brown or gray, 

 mottled with white. It has the habit of hanging motionless in 

 the web for hours at a time, swaying in the wind like an inani- 

 mate object. The strands of its web are rough and inelastic, 

 so that they are frequently broken ; this gives it the appearance 

 of one of those dilapidated and deserted webs in which bits of 

 wind-blown rubbish are frequently entangled. The web repre- 

 sented in Plate IV was unusually perfect, and yet did not 

 appear as it does in the drawing. The pattern was made out by 



