154 



IXVEllTEBIIATE ANIMALS. 



interest as attarkiiii,' man. *)iie of tliese causes the skin-disease 

 wliicli is known a,s the " itch," and tlie otliev is fcnuid inhabiting 



ri^;. 102. — Acariiia. A, Tegi;ocrii,n!s clnngalu^, < 

 Ixodes richnis, imc of tlie Tii'ks, -ii-iitly 

 (Irnrlcs tilhijiiclvs), piilnri,'r(l : I Ijiliim]] ; 

 (.UtiT jncliucl, r.uckaid, ami Cuviw.) 



nf tlie Mites, enlarged 60 times. B, 



iv,;,T.l. C, Mouth-organs of a Tifk 



Mandibles; 7172? Maxillary palpi. 



certain olandiilai' follicles nf the skin, ]ii'ohal)ly without an excep- 

 tion even in fa,\"our of tlie most cleanly [leople. 



( hlliKR J II. PEDII'ALI'I. 



In this family arc the most formidahlc of all tlie Ar<wluiida — 

 namely, the S(ni|.i(iiis (|■ll,^ ](!]). They are all distinguished by the 

 fact that till' .ahdoiiicn is divided into distiiu-t seonients, and is con- 

 timied into the ceplrilcithorax without any well-marked boundary 

 or constriction. In the tiue Si-or]iions the laid of the alidomen (lig. 

 101, t) is composed of a honked telsoii, which is jierforated for the 

 duct of a ]iois(a]-o;lancl, siliiatcd at its base. It is by means of this 

 that the iScorjiious sting ; and the jioisonous tluid which they secrete 

 i.s sufficiently pjowcrful to H'ndcr their ANuuiids jiainful or even 

 d.aiigerous. The m.-i iidililcs in the Scorjiions, ,as ali'eady .said, are 

 d.\ ■■Injieil into pinccr.s, and the s..-calleil " niaxill.-iry ]i.alj)i" con- 

 stilnl. |i.i\vei'fnl nippiiig-cl.aws. 'I'he respiratory organs are in the 

 foiin oi piiliiionaiy saes, four on each side, opening on the under 



