150 Objects for the Microscope. 



ACARUS GAMASUS, 



found abundantly on the Dung-beetle, which it infests. 

 This has a trifid labium, mandibles cheliform, denticulate, 

 the tarsi terminated by two claws, and an elegant pulvillus, 

 which make it worth mounting. 



Scottish peasants have a habit of examining tlie Dung- 

 beetles in the spring, and observing the position of the 

 acari on their bodies : if the parasites are clustered near the 

 head, there will be a fine harvest, if towards the end of 

 the abdomen, a late one. 



TROMBIDIUM PFTALANGII. 



A pretty little parasite, which attaches itself to the 

 Phalangium, or Harvest-spider. These spiders have small 

 oval bodies and very long legs, with two eyes on their backs, 

 and always run upon the ground ; we find these little scarlet 

 mites attached to their legs and bodies. 



TROMBIDIUM AUTUMNALE. 



(Harvest-bug.) 



This troublesome little parasite is found in corn-fields in 

 August, and burrows in the skin, causing much painful 

 irritation. The best way of catching it is to tie pocket- 

 handkerchiefs round the legs, and walk through a stubble- 

 field, when we are nearly certain of finding specimens 

 enough in the folds of the handkerchief. They are mounted 

 in balsam. 



In all the Trombidia, observe the form of the chelicerae, 

 with their moveable claw, and the palpi, which have a sin- 

 gular appendage or finger beneath each extremity, which 

 distinguishes them from the common Acari, and show their 

 relationship to the pretty scarlet Water-mites, theHydrachna. 



WATER-MITES. 



(Hydrachnidce.) 



The beautiful Hydrachna and Limnochares are parasites 

 upon the Water-beetle (Dytiscus), and Water-scorpion 



