Mesostigmata 55 



18. Body shape oval; genital plate of female may be fairly well de- 

 veloped; parasites in respiratory passages of birds and snakes 19 



Body shape elongated oval to wormlike; genital plate of female 

 rudimentary or lacking; parasites in lungs of mammals 



Halarachnidae 



19. Dorsal plate undivided and covering more than podosoma, or if 

 podosomal in position truncate posteriorly with a pair of long 

 setae at its posterior border; parasitic in lungs of snakes 



Entonyssidae 



Dorsal plate usually divided or restricted to podosoma; parasitic 

 in nasopharynx of birds Rhinonyssidae 



20. Setae over body sparse; tectum not shaped like tongue, not pro- 

 vided with long lateral teeth 21 



Setae numerous over body resembhng a pelage; tectum shaped like 

 tongue with long lateral anteriorly directed teeth Haemogamasidae 



21. Chelae reduced Dermanyssidae 

 Chelae not reduced 22 



22. Epigynial plate drop-shaped, may be excavated posteriorly to 

 accommodate anal plate 23 



Epigynial plate truncate or concave posteriorly Phytoseiidae 



23. Peritreme extremely short, less than five times diameter of stigma 



in length Iphiopsidae 



Peritreme long, more than five times diameter of stigma in length 



Laelaptidae 



Discozerconidae Berlese, 1910 



Figures 41a, b 



Diagnosis: The key character — the presence of large bell-shaped 

 suckers flanking the anus — at once distinguishes members of this fam- 

 ily from all others. Even in the absence of the suckers, however, these 

 mites are readily separable from other gamasids in that the sternal 

 plates are divided into a pair of anterior laterals and a pair of posterior 

 laterals fused with the endopodal plates. All tarsi have pretarsi, carun- 

 cles, and small to vestigial claws. Body setae are extremely short and 

 stout. 



