215 



NOTES ON HARVEST=SPIDERS, WITH PARTICULARS 

 OF THEPR OCCURRENCE IN YORKSHIRE. 



(plate XIX.) 



WM. FALCONER, 



Slaithioaite, near Huddersfield . 



Inasmuch as harvest ' spiders' are most in evidence at the time 

 of the ing-athering of the crops, they justif}- the appHcation to 

 them of one part of their trivial name, but they are not, notwith- 

 standing- the popular conception of their identity contained in 

 the other part, true spiders. Nevertheless these creatures have 

 an affinity with each other, and are so nearly related, as both to 

 be placed by systematists in the same g-reat class Arachnida. 

 Once they were reg-arded as insects, even by naturalists, but in 

 more modern times they have been removed from amongst the 

 insects, from which they can with ease and certainty be differen- 

 tiated by the absence of antenuce, the possession of four pairs 

 of leg-s, the union of the head and chest into one piece (the 

 cephalothorax), and their different life history, which is un- 

 marked by any metamorphoses, the eg^g- producing- a juvenile 

 which resembles its parents from its birth, and which without 

 change of form in process of time becomes adult. 



Although the harvestman and the spider possess these 

 characteristics of their class, there is considerable dissimilarity 

 between them, and so apparent is this difference to the unaided 

 sight that there is no likelihood, when once the distinction is 

 made, of either of them being mistaken for the other, even by 

 the most careless observer. In the former (Fig. i) the body is 

 without division, the cephalothorax and the abdomen being 

 fused together ; the latter shows definite, if occasionally in- 

 distinct, traces of original segmentation, and is without spinners ; 

 the eyes, two in number, are placed on an elevation, which is in 

 many species armed with two rows of more or less strong 

 denticulse. In the latter (Fig. 2) the cephalothorax and the 

 abdomen form separate portions of the body, and are connected 

 by a distinct pedicle ; the abdomen shows not the slightest sign 

 of segmentation, and is furnished with spinners ; the eyes in the 

 British species are either six or eight, variously grouped. 



Only a few of the commoner and more active kinds of 

 harvestmen force themselves on our attention in the late summer 

 and autumn, running briskly over the grass and herbage ; the 

 others must be diligently searched for during- the same seasons 

 (except a few which are adult in spring, and one or two which 



1906 July I. 



