METAZOA ARACHNOZOA. 369 



ing upon her. When within the nest the occupant is safe, 

 for the external appearance of the door is like the sur- 

 rounding surface. " If the bank is bare," says McCook, 

 " the top of the door is also bare ; if the bank is covered 

 with lichens the spider cuts a crop of minute lichens and 

 glues them with nice judgment to the outside of her door, 

 thus disguising the entrance." 



It is an interesting fact that the habit of nest-building 

 has become so strongly fixed in the organization of the 

 adult that it is inherited at an extremely early age by the 

 offspring. "That so young and weak a creature," says 

 McCook, "should be able to excavate a tube in the earth 

 many times its own length and know how to make a per- 

 fect miniature of the nests of its parents, seems to be a 

 fact which has scarcely a parallel in nature." * 



The difference in the sexes is not so marked in these 

 more generalized spiders (compare No. 909, 9 , with No. 

 910, ) as in the more specialized forms (see Nos. 913, 

 915, 916, 919, 921, 922), in which the male is extremely 

 reduced in size. 



The brilliantly colored, unnamed spider (No. 912) is 

 allied to Eurypelma. Its abdomen is covered with a 

 thick coating of hair and two long, light colored spinner 

 ets extend outward while the other pair is short. 



Among the spinners the tube-weavers are represented 

 in the Collection by the common grass spider, Agalena 

 naevia Walck. (No. 913, 9, ), and the orb-weavers by 

 five genera of the Epeiridae : Nephila, Epeira, Argiope, 

 Mahadeva, and Acrosoma. 



It is the grass species, Agalena, that makes the hori- 

 zontal webs (PI. 914) on grass that are brought into view 

 by the sparkling dew of the early summer mornings, but 

 which in reality are on the grass all the time, often re- 

 maining for months in favorable localities. PI. 914 

 shows the tube at one side of the web where the spider 



1 Loc. ctt., II, 1890, p. 251. 



