AN INTERESTING AND PRIMITIVE NEW GENUS OF 
LAELAPTIDAE (ACARINA) FROM AUSTRALIA 
AND NEW GUINEA 
By H. WoMERSLEY, A.L.S., F.R.E.S., ENTOMOLOGIST, 
SOUTH AUSTRALIAN MUSEUM 
Summary 
In 1938, Tragardh (Entom. Tidskft, Hft. 3.4, p. 123) published his important paper 
“Further Contributions towards the Comparative Morphology and Classification of 
the Mesostigmata.” In this paper he stressed the importance of the ventral shields of 
this group of Acarina, especially in the female sex, as affording valuable evidence of 
the relationship of the various genera. 
In his view the four pairs of setae found on the jugular, sternal and metasternal shields 
indicate the coxal plates of the four pairs of legs. (It is generally accepted that the 
sternal shield in the Acarina is really formed by the fusion of coxal plates and that a 
true sternal shield does not occur). Generally in the Mesostigmata the sternal shield 
carries 2, 3 or 4 pairs of setae, mostly 3 pairs, the fourth pair often being found on the 
pair of small metasternal shields, as in Pergamasus and Macrocheles. 
