TERRESTRIAL ACARI OF THE TYNE PROVINCE 1 5 



A. — Sub-family Thrombldiinae. 



Mandibles external and hooked. Sensilli situated near the 

 middle of the crista. Eyes (British species) always 4. 



1. Tarsus conspicuously pulvillate ... ,., ... Allothroinbium. 

 Pulvillus absent or very inconspicuous ... .. 2 



2. Body hairs simple spiniform nude ... ... ... 3 



Body hairs otherwise... ... ... ... ... 6 



3. Crista with two pairs of sensilli ... ... ... yohnstoniaiia. 



Crista with only one pair of sensilli... ... ... 4 



4. Eyes conspicuously pedunculate ... ... ... PodothrombUcm, 



Eyes not on common peduncle, sessile ... ... 5 



5. Fore margin of body with a super-rostral process 



(nasus) ... ... ... ... ... ... Rhinothrombutm, 



Nasus absent ... ... ... ... ... ... Eothroinbiitm. 



6. Sensilli situated behind middle of crista ... ... 7 



Sensilli situated before the middle ... ... ... Sericothrombium. 



7. Body hairs spiniform pectinate or plumose JMicrothronibidium. 

 Body hairs crassate, variously formed, villous ...Enemotkrombiu/n. 

 Body hairs (at least behind), ramose above, villous 



below ... ... ... ... ... ... Georgia. 



ALLOTHROMBIUM, Berl, 1910. 



Tarsi with a conspicuous pulvillus under and between 

 the claws. Palpal claw large, without accessory 

 claws or spines. Dorsal setae plumose, pretty 

 dense. Eyes on long peduncles. 



Type : fulighiosum^ Herm. 



I. Allothrombium fuliginosum, Herm. 67. 



British examples appear to belong to var. norvegicum, 



Berl. 

 Yorkshire, Scotland. ' 



SERICOTHROMBIUM, Berl., 1910. 



Palp without secondary claws or spines. Dorsum 

 wide, depressed, usually wrinkled and impressed, 

 indented in the middle of the posterior margin. 

 Eyes on long peduncles. Crista bad to see. 



Type.- holosericeuui, L. 



