tools, is unable to do, and which are not 

 surpassed in skill and finish of workman- 

 ship by those of any of the animal crea- 

 tion. This will be made apparent by a 

 detailed description of its houses on the 

 Pacific slope. They are mathematically 

 correct, are based upon well-known 

 scientific principles, and show an exquis- 

 ite art adapted to the spider's needs. 

 Moreover, the builder seems to know a 

 good deal about organic chemistry, for 

 it makes several compounds of varying 

 materials, for its house, and they always 

 serve the ends for which they are de- 

 signed. Unlike man, it makes no mis- 

 takes in its compounding, mason work, 

 painting and weaving, while its art is 

 perfect of its kind. 



All spiders are carnivorous or insec- 

 tivorous, and employ various devices to 

 capture their prey, which they prefer to 

 devour alive. As the Trap Door Spider 

 is a nocturnal animal, its methods of 

 securing food are not well known, but 

 doubtless they are as skillful as its build- 

 ing operations. These, after a suitable 

 spot has been selected, are begun by dig- 

 ging a vertical barrel-shaped well, bulg- 

 ing from an inch in diameter at each end 

 to an inch and a half at the centre. As 

 the excavation goes on, the spider carries 

 every particle of earth taken out, some 

 distance away and scatters it over a 

 considerable space, so that it may not 

 betray the location of its home. When 

 the digging is finished, it mixes a con- 

 crete of lime, pebbles and bits of broken 

 stone and, adding water, it has a perfect 

 cement, and begins the foundation by 

 filling in this well about one inch solid. 

 It then commences the cylinder with a 

 cup shape bottom. Then it covers the 

 walls with cement, thick enough to 

 reduce the interior diameter about one- 

 half, and makes the surface as smooth 

 as polished marble. The inner rim at 

 the top is accurately beveled, and thus 

 made ready for the placing of the trap 

 door from which the spider takes its 

 name. This door is a marvel of ingenious 

 construction. It is composed of some 

 fibrous substance, gathered or made by 

 the spider, and is covered on both upper 

 and under sides with cement. The upper 

 side is flat and level with the surface of 

 the ground, but the under side is convex, 

 so that the center is strengthened by a 



quarter-inch of thickness and the door 

 thereby weighted to keep it securely shut. 

 Near the outer rim, it is beveled with 

 such skill that it exactly fits the beveling 

 in the wall which has been mentioned, 

 and when shut is both water tight and 

 air tight ; but for an additional protec- 

 tion against the elements there is a thin 

 fibrous extension of the upper rim which 

 projects beyond the wall, and carries off 

 the water like the eaves of our houses. 

 An almost invisible hinge connects the 

 door with the inner wall, and on this it 

 will swing up and down as nicely as any 

 human made door. The substance of the 

 hinge seems to be frictionless, for 

 although it may have been used thou- 

 sands of -times it never shows signs of 

 wear. The scorching rays of the summer 

 sun do not expand it, winter's severest 

 cold does not contract it, and no climatic 

 changes of any kind injure this 

 unequaled hinge. If it swelled or shrunk 

 in the least it would put the door out of 

 adjustment, make the inmate insecure, 

 and bring ruin to its abode, but it is proof 

 against both. Nor does it rot, rust or 

 deteriorate in any way. Through all 

 exposures and invasions of insects the 

 hinge retains its flexibility and remains 

 unchanged, the most wonderful of 

 mechanical contrivances. No scientist or 

 mechanic or both together, can duplicate 

 it, and no other animal big or little has 

 made anything to compare with it. 



Near the hinge on either side, are 

 guards of the same mysterious material, 

 to hold the door in place, and when open, 

 keep it perfectly poised in a perpendicu- 

 lar position; and yet, so perfect is the 

 adjustment that the least touch causes the 

 door to close. These guards are flexible, 

 but do not stretch, and hold the door at 

 any point of stoppage when open. When 

 closed they are automatically folded 

 together, and in the folding a tube is 

 formed on one side about the size of a 

 pin, which is open at both ends for the 

 purpose of letting air into the cylinder 

 where the spider lives, but it is turned 

 down at the outer end so that when it 

 rains, water will not get into the house. 

 Beside the tube is a latch which is the 

 spider's open sesame for entrance when it 

 comes home from its excursions. It is 

 so minute a protrusion that it is not dis- 

 cernible to the naked eye, and can only 



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