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thofe parts in a Flea which I heretofore took to be the piercers or 

 weapons by which it draws the blood, appeared now to be the 

 flieath or cafe of the real piercers, which divide into two parts when 

 the Flea thrurts out its piercers from between tliem. I will now 

 defcribe how thefe parts appeared to me upon the examination of 

 three feveral Fleas. 



Fig. 17, ABC are the two horns on the head, which have been 

 fliewn in the laft figure, each of them has three joints, befides the 

 joint fixed to the head ; D E is the fheath or cafe, with the llings 

 or piercers, which in a manner fit or lock into each other, as I ob- 

 fei-ved while I was endeavouring to feparate them. FAD is part 

 of the head. 



Fig. 18, G H I K, reprefents alfo the piercers, and their cafe or 

 flieath, placed in the head, between the two fore feet ; which 

 piercers and their llieath are very difiicultly difcovered, unlefs the 

 fore feet be firft cut off clofe to the head, and even thus they will 

 feldom be fecn ; becaufe the Flea, when not viling its piercers, draws 

 them within the flieath, and places them clofe to its body. But as 

 a Flea, though its fore feet are cut off, will yet live a long time, 

 my way always was, when I endeavoured to get a view of the 

 piercers, to cut off its head, lefl:, when I had removed the piercers 

 from their pofition clofe to the body, and feparated them from each 

 other, the Flea fhould draw them again out of fight. 



G I, and G K, are two parts, which, having cavities in them, 

 oppofite to each other, conftitute the fheath of the piercers ; which 

 piercers are placed in the cavity marked at G H. Thefe two flings 

 or piercers might indeed be taken for a tingle one ; but if we view 

 tlie figure narrowly, it will appear that the Jimner has pictured the 

 fecond fl:ing as it were within the fijlt, and not reaching quite to, 

 the end at H. 



Fig. ig, LMNOP, exhibits the fheath of the flings or piercers 

 as I found them in a third Flea. Here I had better fuccefs than in 

 the diflection of the two former Fleas. For at L N and L O are 



YoL. II. F 



