THE GENUS DEMODEX. 'iO 



DEMODEX CANIS var. ERINAOEI, Hirst, 1917. 

 D. eiinacei, Hirst, Ann. Mag. Nat. Hist. (ser. 8) vol. xx. p. 434. 



(Plate IV. figs. 17, 20, 21.) 



$ . The Bemodex occurring in the hedgehog is an elongated form 

 closely resembling that of the dog {B. canis) in almost every respect, 

 but of larger size and with the capitulum wider as compared with its 

 length, being very distinctly wider than long (at the base), instead of 

 only slightly wider as in B. canis ; the sculpturing of the dorsal 

 surface of the capitulum apparently is also rather different; the two 

 spines are much like those present in B. canis, being quite short. 

 Body from over six to slightly more than seven times as long as wide. 

 Cephalothorax+capitulum about a third of the total length. Trans- 

 verse striations of body extending forwards beyond the coxie of the 

 fourth pair of legs, the first striation being deep and well-defined. 



d . Body long and slender, as in the female, being a little more 

 than six times as long as the width of the cephalothorax. Abdomen a 

 little more than twice the length of the cephalothorax+capitulum. 

 Male sexual orifice placed well in front of the transverse furrow between 

 coxiE of first and second pairs of legs. Penis very long and slender. 



Author's measurements — 



Female. Male, 



Totallength of body (incl. capit.) . . . 313-335 /x about 330 /x 



(specimen sligbtly bent). 



Length of cephalothorax -|-capituliini . . 108 /j. 116 fi 



,, abtlomen 205 /a about 214 /x 



Greatest width of cephalothorax ... 44 /x 63 /a 



„ ,, abdomen 46 /x. ? 



,, „ capitulum (at base) . 35 /x 42 /x 



Length of capitulum 26 /x 29 /x 



„ penis — 32 /x 



Host : Hedgehog (Erinaceus eurojicBMs). Several specimens were obtained from an 

 English example of this aniuial. 



3. DEMODEX LONGIOR, Hirst, 1918. 

 Ann. Mag. Nat. Hist. 1918 (ser. 9) vol. ii. pp. 145 & 146. 



(Plate IV. figs. 18 & 19.) 



$ . An elongated species of comparatively large size, resembling 

 B. canis in many respects, but the coxae (epimera) of the legs are 

 narrower and produced posteriorly, especially the first ones. Body 



