THE CANADIAN ENTOMOLOGIS'J', 



sider what interesting objects they form for microscopic work. As in 

 most groups of Arthropoda, the pioneer work in this country was done by 

 Thomas Say, whose descriptions of a number of the larger species appeared 

 as early as 1821. Later on Dana and Whelpley (1836), and Haldeman 

 (1842), contributed descriptions of a few species. More recently Dr's. Fitch, 

 Leidy, Packard, Riley, LeBaron and Shimer, and Mr. Ashmead, have 

 pubhshed descriptions of species and notes on habits, while quite lately 

 Mr. Harry Garman has published a valuable paper on the Phytoptidje, 

 which it is hoped he will follow up by still more extensive study of this 

 family. 



It is hoped that the following list of the Acarina of the United States 

 and Canada — which we have made as complete as possible up to date — 

 may encourage the further study of the group, and as an additional aid it 

 may be in place to make a few statements concerning their habits and the 

 methods of studying them. 



The Trombididse are found on plants or free as adults, frequently in 

 the larval form, as parasites on insects. The Hydrachnidje are aquatic, 

 and probably many interesting parasitic forms will be found by careful 

 examination of the gills of bivalve mollusks. Of the Gamasidae occurring 

 as parasites on insects but few of the probable number have yet been 

 described. In the Acaridae we have many parasitic forms on birds and 

 mammals, and here especial care should be taken to identify with 

 described European forms whenever possible, particularly in all cases 

 where the bird or mammal host is identical in the two countries. Doubt- 

 less many described species occur commonly here which have never been 

 recorded, e. g. Myobia muscidi seems never to have been recorded in 

 America, but has been taken at Ames, Iowa, and hence is included in our 

 list. A few species common to domesticated animals that are being con- 

 stantly imported from other countries have been included in this list, even 

 when we have been unable to find a positive record of their occurrence 

 here. 



The Phytoptidae are microscopic in size, and occur on buds, leaves 

 and fruits, producing galls, deformations, blisters or rusts, and their study 

 offers an almost unlimited field for careful investigation. 



A large proportion of the mites are too small to be readily studied or 

 preserved, except as microscopic objects, and the most desirable method 

 is to mount them at once, or as soon after collecting as possible, in 

 glycerine jelly or prepared balsam. It is frequently a great advantage to 



