TERRESTRIAL ACARI OF THE TYNE TROVINCE 



55 



B, — Sub-family Zerconinae. 



Here I include Celaeiwpsidcc, Berlese, Rhodacarince, 

 Oudemans, and Thinozerconidce, Halbert ; also the genus 

 Dendrolaelaps, Halb. Some or all of these sub-families may 

 be justified by-and-by, but at present it seems to me that the 

 available material is hardly sufficient to fix the comparative 

 value of the characters on which the divisions have been 

 based. 



The dorsal plate may be entire or divided, but if divided 

 the parts are contiguous so that always the whole dorsum is 

 covered, and the covering plate may be, at least in part, con- 

 tinuous with ventral plate. The ambulacrum of the first pair 

 of legs is always reduced, but never, I believe, wholly lacking. 

 The genital aperture of the male is always in the sternal 

 scutum but sometimes lies close to the fore margin, thus 

 approximating to the Gamasine position. The epigyne is 

 always post-sternal. In the adult stage there is never any 

 unchitinized expansible skin (except in some species of 

 Setodes). 



6. 



Body elongate, dorsum quite smooth 

 Body broader, dorsum more or less rough ... 

 Body oval convex, dorsum smooth ... 

 Rostrum large and conspicuous 

 ,, of normal size 



Peritreme dorso-lateral ... 



Peritreme absent 

 Peritreme normal 

 Dorsal scutum not transversely divided 



,, divided transversely in the middle ... 



Body trigonous, broad behind 



,, oblong or oval 



Dorsum with a diverse margin and posterior spines 

 ,, with only a serrate and setate margin 



2 



3 



Celaenopsis . 

 Rhodacariis. 

 Dendrolaelaps. 

 Thinozercon, 

 Epicrius. 

 4 

 5 

 6 

 Trachytes. 

 Setodes. 

 Seius. 

 Zercon. 



SEIODES, Berlese, 1877. 

 Type ; ursinus, Berl. 

 I. Dorsal setze obtuse, dorsum rounded in front 



... hislriciiius. 

 lender acute, dorsum truncate in front., pimctatus. 



