x INTRODUCTION. 
Gen. MerGIsTHANUs. 
Oriental Region (Malacca). 
Australian R. (New Guinea, Queensland). 
Neotropical R. (Mexico, Guatemala, Paraguay). 
AKthiopian R. (Gold Coast *). 
Gen. Dermanyssvs. 
Palearctic Region (Europe). 
Nearctic R. (U.S.A.). 
Neotropical R. (Guatemala). 
Fam. SARCOPTIDZ. 
Gen. TyRoGLyPHUus. 
Palearctic Region (Europe). 
Nearctic R. (U.S.A.). 
Neotropical R. (Guatemala). 
Gen, Mrenin1a. 
Palearctic Region (Europe). 
Neotropical R. (Guatemala). 
Gen. Preroticuvs. 
Palearctic Region (Europe) . 
Nearctic R. (U.S.A.). 
Neotropical R. (Guatemala, Brazil, Guiana, Ecuador, Patagonia). 
Oriental R. (Himalaya, India, Java, Philippine Islands, China). 
Australian R. (New Holland, New Guinea, New Zealand, New Caledonia, Tahiti, &c.). 
AAthiopian R. (Gold Coast and other parts of Africa). 
Gen. ProctoPHYLLODEs. 
Palearctic Region (Europe). 
Neotropical R. (Guatemala). 
There can be no doubt that the geographical distribution of the various families, 
genera, and even species of many Acarids will eventually be found to be much larger. 
Several are already known to extend over more than one of the z00-geographical 
regions, 2. €.:— 
Atax crassipes, O. F, Mill. t—Europe, Guatemala. 
Actineda baccarum, L.t—Europe, Guatemala, Paraguay (Rio Apa), Buenos Ayres. 
Holostaspis marginatus, Herm.—Europe, Guatemala, Brazil (Matto Grosso), Paraguay 
(Asuncion, Rio Apa), La Plata (Buenos Ayres). 
Undoubtedly the migrations of the Acarids may account, to some extent, for the 
uniformity of types, especially as regards the wholly or partially parasitical species. 
* I possess a new and very interesting species belonging to this remarkable genus from Accra (Gold Coast), 
which I propose shortly to describe elsewhere. 
T See page 47. t See page 45. 
