Superfamily Avicularioidea 



In the cork type, the door is thick, and its edge is bevelled 

 so as to fit accurately the bevelled opening of the tunnel (Fig. 

 216). Near the edge of the inner surface of the door, at the 

 point farthest from the hinge, there are two holes; these are to 

 receive the claws of the chelicerae when the spider is holding the 

 door closed; and, according to the observations of Moggridge, 

 the door in the cork type consists of many layers of silk each 

 furnished with a sloping rim of earth. He represents fourteen 

 layers of silk and earth which went to make a single cork door 

 examined by him. These layers were successively larger and larger 

 beginning with the innermost, and he believes that the latter 

 constituted the first door the spider ever made, and that the 

 consecutive layers mark successive stages in the enlargement 

 of the nest. His observations were made on the nest of a French 



Fig. 218. DIFFERENT TYPES OF NESTS OF TRAP-DOOR SPIDERS (after Moggridge) 



species. I have been unable to satisfy myself that the same 

 thing is true of the door of our California species. I have, how- 

 ever, taken apart only the door of a single nest. 



Figure 218, which is copied from Moggridge C74), repre- 

 sents the different types of nests of the trap-door spiders of this 

 subfamily; another type, described later, is made by a member 

 of the Brachybothriinae. At a is represented the nest of a French 

 species of Atypus, one of the Atypidae; this is included here merely 

 for contrast; b represents the cork type of nest; Moggridge be- 

 lieved that in this type the tunnel is always simple, but Atkin- 

 son ('86) describes a branched nest with a door of the cork type. 



234 



