28 



BRITISH TYJROGLYPHID^E. 



GENERAL REVIEW OP THE ACAEINE SYSTEM. 



Orders. Sub-orders. 



I. Astigmata 



-II. SARCOPTINA 



II. Hydracarina 



III. Prostigmata 



IY. Cryptostigmata 

 V. Metastigmata 



VI. Mesostigmata 



1. TROMBIDINA 



II. HOPLOPINA 



No. of 



Families. Genera. 

 1 



3 

 3 



3 

 17 

 12 



7 

 2 



23 

 4 

 8 

 2 

 7 

 6 

 9 

 5 

 2 

 4 

 3 

 1 

 2 



12 

 2 

 6 

 2 

 1 



4 

 9 

 5 



3. Cytoleichidcfi 



4. PsoroptidaB 



5. Linocoptida) 



6. Listrophoridae 



7. DermoglyphidcB 



8. Analgesidas 



9. Tyroglyphidae 

 ( 1. Halacaridse 



j 2. Limnocaridae 

 ^ 3. Hydrachnidae 



1. Tarsonemida3 



2. CheyletidsB 



3. Erytbrseida3 



4. Tetranychidse 



5. Raphignathidai 



6. Eupodidas 



7. BdellidaB 



8. Alychidaa 



9. RbyncholophidaB 



10. Trombididse 



11. Hoplopidaa 



{1. OribatidsB 

 2. Notnrid33 

 3. HoplophoridaB 

 / 1. Ixodidas 

 I 2. Argasidaa 



1. Nicoletiellidae 



2. Uropodidae 



3. Zerconidse 



4. Lelaptidas 



5. Gamasidae 



6. Dermanyssidas 



Genera of doubtful position are not included in tbe number of genera. 



There is no doubt that this is an excellent classifica- 

 tion in most respects. There are, however, certain 

 points in which I should not be altogether inclined to 

 follow it. The Acarina are treated as a class ; this 

 follows the opinion of Haller * and Oudemans.f It 

 matters but little, perhaps, what a group is called, 

 whether a class, an order, or a family ; because our 



* "Die Mundtheile und systematiscbe Stella ng der Milben," in 

 ' Zool. Anz.,' 1881, No. 88, pp. 380-336. 



f " Die gegenseitige verwandschaf t Abstammung und Classification 

 der sogenannten Arthropoden," in ' Tijdschr. Nedeiiand. Dierk. Ver.,' 

 ser. 2, Deal 1 (1886). 



