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Pomona College Journ.vl op Entomology 



abundance of hair are found to some degree living in similar situations, but 

 plume-like seta? are found in many different groups of Arthrojjods, and in 

 certain families such as the Therophosidie and ThrombidiidtT', they are very 

 marked. 



12 



Figure 256. Setae from spiders and Limulus 



All are enlarged 325 times. 1 and 2, hairs from tlic leg of one of the Lycosidae, the 

 base of 2 is shown; 3, 4 and 5, setae from one of the Epeiridae, the bases of 3 

 and 4 are shown; 6, 7 and 8, hairs from one of the Thonididae; 9, one of the very- 

 few plume-like hairs from one of the Agalaendac; 10, 11 and 12, setae and parts 

 of setae from Limulus. 



Among arthropods there has been, in the past, evidence from the Golgi 

 and methylene blue methods that nerve fibres from bipolar sense cells pene- 

 trate set«; some of the evidence by Bethe ('96), Duboseq, Holmgren ('98), 

 Schreiber ('98) and many others. Some Golgi preparations gave impregna- 

 tion results which seemed to show that the whole hollow of the hair was filled 



