XII] SPIDER 261 



of appendages, the pedipalpi, are leg-like and modified in the male 

 in connection with the fertilization of the female. The abdomen 

 bears certain modified appendages called spinnerets, on which 

 open the glands, the secretion of which produces the Spider's web. 

 If we examine such a Spider as Epeira diademata, which is common 

 enough in English gardens, sitting on or near its well-shaped web 

 (Fig. 1 1 3), we notice that behind the prosoma 

 there is a slender waist and that this is 

 followed by a large swollen abdomen with 

 no outward trace of division into segments, 

 or into meso- and meta-soma. 



There are six pairs of appendages, and 



External it is at once noticeable that 

 there are no antennae or feelers 

 to act as sensory organs. Their function is 

 to some extent taken over by the long walk- FIG. 114. Front view of 

 ing legs. The first pair of limbs are called "* < t $>* 

 eh el i c era e ; in Epeira these are two-jointed, Magnified. From 

 the terminal joint being pointed and folded 

 down against the basal joint except when 1 - Head - 2 - E y es - 



, . 8 , /TV ,,x mi r 3 - Basal J lnt f che ' 



being used (rig. 114). Tnis pair 01 appen- Hcerae. 



dages contains poison glands and the poison 4 - Claw of chelicerae. 



escapes through an opening at the point of the second joint. By 



means of it the Spider can kill insects and seriously hurt larger 



animals. 



The second pair of appendages in the Arachnida are called 

 pedipalpi (Fig. 115). In Epeira they resemble the walking legs, 

 but in the male at the final moult the last joint becomes altered 

 and forms a hollow sac the palpal organ which plays an im- 

 portant part in fertilizing the female. 



Then follow four pairs of walking legs each with seven joints 

 and terminated with two or three claws ; in some species they are 

 provided with a pad of short hairs called a scopula, which helps 

 the animal to run on walls and ceilings. 



The mouth is very minute, for the Spider does not swallow solid 

 food but sucks the juices of its prey. It lies between the bases 

 of the pedipalps, and the basal joint of each of these appendages 

 has a cutting blade termed the "maxilla" (2, Fig. 115). It is 

 a common feature of the Arachnids that the basal joints of one 

 or more of the pairs of appendages develop gnathobases and act 

 as jaws, but the modification never goes so far as to obscure 



