MITES AS DECADENT SPIDERS 



'295 



specialised, yet are more, not less, capable in consequence. 

 But they are at a perilous point of perfection. In the 

 animal series, as in the history .of art, decadence often 

 follows suddenly upon periods of the highest attainment, 

 and ia virtue of the same law of development. From the 

 spiders' have arisen small spider-like creatures — the mites 

 and tics— which no longer, " trapi".or hunt their prey, but 

 have learnt to attach themselves to the bodies of larger 



L&By& lAUNW. 



LABVA. CHTBA 



Fig. 41 .—Development of- the barnacle from a f ree-swimmingf stage 

 with six active legs. The larva 6t Balanus and of Chthamalus., 

 closely allied to the true Lepas barnacle, are drawn sinc% tjieydo 

 pot differ from that of Lepas. In the drawihg labelled " pup^ " the 

 head with its two feelers outspread is seen fixing the young animal 

 by a cement, which it secretes, to a piece of wood.' 



finimals and plants and to feed on therr abundant juices; 

 Some have gone further and feed on hair, $kifi, and 

 feathers, or even on the powdery masses of dead veger 

 tables, and whilst retaining the general shape of spiders 

 have lost the extraordinary agiHty, the keen sigiit ^n<l 



