198 The Ar<n'hnnl<i of Cambridgeshire 



in houses, while everyone knows the web of Ayi'li'im. /<t//ri>i- 

 thic<t, to be met witli so frequently on the hanks of dit< i 

 The well known water-spider, Ar<jiir<nn-t<i, u<i\int'n-ti, coiiiinon 

 in the neighbourhood, belongs to this family, as does also the 

 handsome Tf.rtrir dcHticuhtta, a welcome addition to nin>t 

 collections, though not rare at Cambridge under the 1- 

 hark of trees. 



THERIDIIDAK. The great majority of British species belong 

 to this family, and three of its sub-families, Theridioninae, 

 Erigoninae and Linyphiinae, are very well represented about 

 Cambridge. 



The Theridioninae, of which the principal genus is Thi-ri- 

 (//"//, include tlie prettily variegated, somewhat globular spiders, 

 whose irregular webs are to be found on almost every holly 

 bush. Perhaps the most beautiful example, Tkeriditm J'orntn- 

 sum, is in some seasons extremely common, though ordinarily 

 seldom met with. 



The Erigoninae comprise the multitudinous tiny black or 

 brown spiders, sometimes called "money-spinners." Some of 

 these are very curious when examined under the microscope, 

 the heads of the males in certain species being furnished with 

 variously shaped prominences on which the eyes are mounted. 

 An extreme example is Walckenaera acuminata, the height' of 

 whose slender eye-turret equals the length of the cephalo- 

 thorax. One of the smallest known spiders, Panamomops 

 bicuspis, about ^ in. in length, is a local rarity. 1 1 'iflrrin 

 warburtonli has not yet been found elsewhere. On fine day- 

 in the autumn many of these spiders, together with the newly- 

 hatched young of larger species, may be observed on iron 

 railings busily occupied in aerial migration. Standing on 

 tip-toe, so to speak, the spider raises its abdomen and emits 

 a slight. Hake of silk, which is gradually drawn out ly light 

 currents of air till the pull is sufficient to support the weight 

 of the spider, which then lets go its hold and floats gently 

 away. 



The Linyphiinae include those spiders which are con 



