4 



PRESIDENTIAL ADDRESS. 



The families included in the order " Acarina " are divided into 

 " Tracheata " and " Atracheata," and are as follows : — 



I. — Gamasidae 



Tracheata. 



Gamasinae, with 

 Pteroptinae and 

 Dermanyssus - 



2. — Ixodidae, including Argas - 



3. — Oribatidae 



4. — Trombidiidae - Tetranychi 



5. — Cheyletida^. 

 6. — Hydrachnidae 



7. — Myobiidae 



8. — Tyroglyphidae 

 9. — Sarcoptidae 



Trombidiinse 

 Bdellinae - 



Limnocharidre 

 Halicarinae 



Atracheata. 



Predatory Mites ; 

 Mites parasite on 

 Bats and other 

 Vertebrates. 



Ticks. 



Beetle Mites. 



Spinning Mites. 



Harvest Mites. 



Snouted Mites. 



Water Mites. 

 Mud Mites. 

 Marine Mites. 

 Louse Mites. 



- Cheese Mites, etc. 



Bird-Louse Mites. 

 Itch Mites. 

 Water Bears. 



- Analginae, with 



Mycoptes and Lis- 

 trophorus 

 Sarcoptinae 

 10.— Arctisconidae - - - - 



II. — Demodicidae. 



12.— Phytoptidae Gall Mites. 



It may possibly be useful to indicate some of the localities 

 where the various families may be found. 



The members of the Gatnasidm are usually active and preda- 

 tory, ranging about free in damp places, in moss and under stones, 

 while in the nymphal condition large numbers may often be found 

 upon beetles, such as Geotriipes sfercorariiis, etc., and upon the 

 various hybernated Bombi. They have filiform palpi, and in 

 Gamasus the first pair of legs are usually tactile organs, while the 

 second pair in the males are often swollen and enlarged, and pro- 

 vided with singular appendages and hooks. This is a very 

 marked feature in G. terribilis, which is usually met with in moles' 

 nests. The spear-shaped mandibles with which the males are 

 armed are used by this creature for thrusting through its prey. 



