166 SPIDERS 



infantry with machine-gun fire. The prey is stuck firmly to the 

 ground while the spider advances and eats it at leisure. 



The various uses of silk employed by spiders in the capture of 

 prey have already been mentioned. The Ctenizidae dart from their 

 tubes and capture insects passing near the trap-door while the 

 Atypidae strike through their purse-webs at any small animal 



Fig. 36. Scytodes thoracica binding its prey with gum which it 

 squirts from the fangs. (From Cloudsley-Thompson, 1953.) 



crawling over the exposed part. Segestria senoculata and other 

 members of the genus make their tubes in crevices of walls and 

 rock faces. The rim of the open entrance is stretched outwards 

 by half a dozen or more long stout straight threads. When an 

 insect or woodlouse touches one of these the spider darts forth to 

 seize and retire with it. A similar method is employed by the 

 Filistatidae, such as the well-known Mediterranean species Fili- 

 stata insidiatrix. 



Sheet-webs are built by several families, and in Britain by some 

 of the Agelenidae, Linyphiidae and Pholcus phalangioides (Phol- 

 cidae). In the first family the spiders run in an erect position on the 

 upper surface of the sheet, but in the other two they are suspended 

 in an inverted position from the lower surface. Scaffolding webs 

 are characteristic of the Theridiidae. In Stearodea hipunctata, for 

 example, a sheet of wide meshes is kept taut from above and below 

 by a number of threads extending vertically to the ground. These 

 have viscid droplets for part of their length and break off easily 



