Introduction 1 1 



5 grams methocellulose 



2 grams carbowax 4,000 



1 milliliter diethylene glycol 

 25 milliliters 95 per cent ethyl alcohol 

 100 milliliters lactic acid 

 25 milliliters distilled water 



They found the best procedure was to clear thoroughly in lactophenol 

 before mounting, although some of the more delicate mites needed no 

 special preparation as the lactic acid in the medium cleared the speci- 

 mens sufficiently. 



Newell 1947 has devised a method for making permanent glycerin 

 mounts. Untreated mites cannot be mounted satisfactorily in oil-solu- 

 ble resins because the refractive indices of these substances are too 

 close to those of the ectoskeletal elements of mites. If mites are 

 mounted in such materials as damar or balsam they must first be 

 cleared in lactic acid or mild caustic to remove the soft tissues. Their 

 exoskeletons must then be stained so that they will contrast with the 

 mounting medium. If a phase-contrast microscope is available, how- 

 ever, unstained specimens can be studied satisfactorily in such mount- 

 ing media. 



As soon as slides have been made they should be labeled. It is 

 conventional to put the collection data on the right-hand label and 

 reserve the left-hand label for the name of the mite. 



Terminology: Acarology has been developed largely as an outgrowth 

 of entomology. Therefore the terms used in describing the anatomy of 

 mites and ticks have been borrowed from entomology. Unfortunately 

 entomological terms when applied to mites frequently have entirely 

 different meanings from the term as originally used. Analogy rather 

 than homology has been the usual criterion for transferring a term 

 from one group to the other. It would be possible to create an entirely 

 new vocabulary that applied properly to the Acarina, but this would 

 create more confusion than now exists. Consequently names which 

 have more or less general acceptance among acarologists will be used 

 and will be defined as they apply to the Acarina without regard for 

 their original entomological meaning. In most cases Vitzthum 1940 

 will be followed. 



Metamerism: Many acarinids appear to consist of a single segment. 

 Others have the body apparently divided into a cephalothorax and 



