190 



Acarology 



Discussion: Speleognathus australis Womersley has been collected 

 in moss and from around cattle watering tanks in Australia. Speleo- 

 gnathus sturni Boyd is to be found in the nasal passages of starlings in 



the eastern United States. Boyd 

 1948 found that the birds with 

 these mites had more nasal secre- 

 tion, or mucus, than those not 

 parasitized. There is apparently a 

 close relationship between this 

 group and the Ereynetidae in 

 structure and biology, for Riccar- 

 doella limacum (Schrank) in- 

 habits the snail, whereas S. sturni 

 is in the warm mucus of the nasal 

 passage of the starling. Boyd 

 points out the possibility of a 

 common ancestor of the two 

 mites. This species may be rather 

 generally distributed and will 

 probably be found wherever the 

 starling or related birds are es- 

 tablished. 

 The larval form of S. sturni Boyd, although basically similar to the 

 adult, shows an interesting deviation in that tarsus i does not possess 

 claws or pulvillus but tibia i has a long, bifurcate, clawlike process. 



References: 



Boyd, Elizabeth. 1948. A new mite from the respiratory tract of the star- 

 ling (Acarina, Speleognathidae). Proc. Ent. Soc. Wash. 50(1):9-14. 



Womersley, H. 1936. On a new family of Acarina, with description of a 

 new genus and species. Ann. Mag. and Nat. Hist. 18(104) :3 12-3 15. 



Figure 129 Speleognathus sturni Boyd. 

 Venter of female. (From Boyd 1948) 



Tydeidae Kramer, 1877 



Figures 130, 131 



Diagnosis: The tydeids are weakly colored in yellow, brown, red, or 

 green. They are very small mites measuring from 0.100 to 0.300 mm. 

 in length (they are usually about 0.20 mm. long). They are of various 

 shapes but usually an egg-shape predominates. The skin is soft with 

 punctate striations, and in some species it has a punctate or reticulate 

 pattern. There are few body setae and a pair of sensory setae is located 



