Sarcoptiformes 329 



basal seta with the occasional addition of a parasub-basal seta; (iii) a 

 group of four median setae; (iv) a ventral-terminal group of three to 

 five spines; (v) a dorsal-terminal group of four long setae that may be 

 modified; (vi) a claw surrounded by a caruncle that is never pedun- 

 culate. Tarsus ii bears a macrosense seta but does not have either a 

 microsense seta or a parasub-basal seta. Tarsus in in heteromorphic 



r^^ASM 



Figure 261 Rhizoglyphus echinopiis 

 (Fumouze and Robin). Ventral view 

 of heteromorphic male. 



Figure 262 Rhizoglyphus echinopus 

 (Fumouze and Robin). Ventral view 

 of gravid female. 



males is modified as a large claw. Tarsus iv in the female bears two lat- 

 eral spines; in the male these are replaced by two suckers, except in the 

 genus Thyreophagus where there is only one. In the more primitive 

 members of the group the tarsal setae are thin, slight hairs; in the more 

 advanced members they become modified as large spines. Larvae have a 

 well-developed, cylindrical, or pin-shaped "Bruststiele" (urstigmata). 



Key to the Acaridae 



1. Without sexual dimorphism; inner propodosomal setae as long as 

 or longer than outer; legs slender with hairlike setae, lateral and 

 mesial median setae of tarsi unmodified; microsense and macro- 

 sense setae not arising from same base Acarinae 



