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THE BRITISH TRAP-DOOR SPIDER. 



By Feed. Enock, F.L.S., F.E.S. 



II. 



THE form of the tube inhabited by the British 

 trap-door spider varies according to age. An 

 immature male or female spider makes a parallel 

 burrow, but on reaching maturity — which in the 

 female is not attained for some years — she enlarges 

 her burrow at about half way down, on the upper side, 

 making a cavity an inch or more long and a quarter of an 

 inch deep («< Fig. 1, p. 251). Across this she slings a 

 hammock of the finest floss silk spun from the smallest 

 pair of spinnerets (Fig. 7). In the hammock she then 

 lays from one hundred to one hundred and fifty eggs, of a 

 very pale yellow colour ; these are laid during the sum- 

 mer, and hatch in the autumn into spiders which cast their 

 swaddling clothes before emerging from the hammock 

 later on. The mother broods over her young, and, so far 

 as my experience goes, she always seems to have them 

 well in hand during the winter months ; but on the 

 approach of warm weather in April she in some way 

 intimates to them that it is time they emerged from the 

 maternal home, to go and find their own living — which 

 they do in exactly the same manner as taught them by 

 their mother. 



On reference to Fig. 6 we notice the wonderful mechan- 

 ism of the jaw, which internally is lined with bands of 

 striated muscle, the ends being bound round the termina- 

 tion of the joint of the long fang. At the tip of the jaw, 

 embedded in the muscle, is to be seen the poison bag and 

 duct, the latter running through the ball-and-socket joint 

 and down the hollow fang, from which the poison flows 



througha minute aperture, placed just before the sharp point. 

 The lower jaws, to which are attached the palpi, are 

 somewhat thumb shaped, opening laterally at right angles 

 to the movement of the xqqKV jaws, which are thrown up 

 in much the same manner as a navvy working his pickaxe. 



How this spider obtained its food was for a long time a 

 complete puzzle — only to be solved by careful observation. 

 When living at Woking, I found this spider exceedingly 

 plentiful about the uncultivated commons, where they had 

 not been noticed in any way. For many years it was 

 commonly supposed that this spider fed upon earthworms. 

 One author went so far as to write : " I frequently sur- 

 prised Atypiui in the act of holding earthworms in their 

 falces"; but before this could have been seen the nest 

 must first have been dug up, and, if so, I cannot under- 

 stand how the spider would retain its hold after the tube 

 had been torn open. 



No doubt earthworms, in their subterranean borings, 

 might occasion- 

 ally come into 

 contact with the 

 tube of the trap- 

 door spider, and 

 then the inmate 

 would seize hold 

 of the worm. In 

 fact, I have tried 

 the experiment 

 several times, 

 and found that 

 as soon as the 

 worm pressed 

 against the silken 

 tube the spi.lcr 

 caught hold of 

 it, and, in spite 

 of its twisting 

 about, puUed it through to the bottom of its burrow, 

 where a great scuffle went on, resulting in the worm being 

 cut up into mincemeat by the terrible jaws of the spider. 



Having such facilities for studying the habits and 

 economy of small animals, I soon had a large colony of 

 trap-door spiders established in a bank of turves which I 

 buQt up at the bottom of my garden. Here I was enabled 

 to watch them day and night without interference. Each 

 tube was numbered, so that I could give an account of 

 each one's doings from day to day. On capturing a very 

 large female I turned it out upon a sheet of paper, upon 

 which it had great difficulty in walking, its large body 

 dragging so much — and it had not the power to raise it. 

 Touching the spider with a blade of grass caused it to lose 

 temper ! Cautiously I repeated the annoyance, and noted 

 that the spider immediately raised its cephalo-thorax — or 

 shall I say its " head " :' — in a most threatening manner. I 

 applied the stem again, with the result that the two huge jaws 

 were thrown up vertically, the fangs, too, unfolding from 

 beneath, while the lower jaws, armed to the edges with a 

 most horrible array of spikes, were opened wide — so wide 

 that I could look right into the throat ! On further applica- 

 tion of the grass stem the diabolical machinery was closed 

 with a snap, and the stem severed in two. The movement 

 was so interesting that I caused it to be repeated several 

 times upon two thicknesses of blotting paper, which was 

 pierced right through by the fangs ; a penholder was also 

 marked. Then, when the anger of the spider was furious 

 to behold, I ofl'ercd the tip of my finger to soothe it ! This 

 was quickly seized, the fangs (an eighth of an inch in 

 length) were driven in up to the hilt, while the spikes on 

 the lower jaws rasped across on the other side. The 



Fio. 6.— Mechanism of the Jaw of the British 

 Trap-door Spider, showing Fang and Poison 

 Bag. 



