14 F. P. SMITH ON THE SPIDERS OF THE SUB- FAMILY ERIGONINAE. 



against the glass by a central plug of cotton wool. The bottle 

 is nearly filled with methylated spirit, so as to completely sub- 

 merge the tubes, each of which is separately plugged with wool. 

 The labels, written either with pencil or Indian ink, are dropped 

 in the tubes with the spiders. To give some idea of how much 

 space should be allowed, I might say that the sub-family 

 Erigoninae, with which we are at present chiefly concerned, 

 contains about 120 species, all of which could be satisfactorily 

 stored in tubes of the above-mentioned size. 



The spiders included in the family Linyphiidae, to which the 

 Erigoninae belong, are all of a small or moderately small size, 

 amongst them being the most minute representatives of the 

 Araneae. The eyes are normally eight in number, arranged in 

 two transverse rows ; but one or more pairs may be atrophied, 

 and even the whole of these organs may be absent. The form 

 of the caput in the male varies to a surprising extent in different 

 species, but, with a few exceptions, that of the female is quite 

 normal. The legs are more or less furnished with spines, but 

 in many cases these are very small, and often there is only one 

 upon the tibia of each leg, the other joints being quite devoid 

 of them. In addition to these spines and the ordinary hairs, 

 the legs are sparsely furnished with minute organs, which I 

 propose to denominate sensory setae. These peculiar structures 

 are described and figured by F. Dahl,* who believes them to be 

 organs of hearing. W. Wagner,t however, gives it as his opinion 

 that they are more probably connected with some other sense, 

 and suggests that by their aid the spider may be enabled to prog- 

 nosticate atmospheric disturbances. Personally, I am inclined 

 to ascribe to them acoustic properties, but I do not feel justified 

 in expressing any strong opinion upon the matter until further 

 opportunities for investigation shall have cleared up some of 

 the difficulties with which at present the subject is beset. For 

 the benefit, however, of any one who may be anxious to aid in 

 the unra veiling of one of the many mysteries of spider structure, 



* Arch. mikr. anat., xxiv., pp. 1-10. Translation in Ann. Mag. Nat. 

 Hist., Ser. V., vol. xiv., pp. 329-37. 



t Bull. Soc. Imj). Nat., Moscow, 1888, pp. 119-31. 



