METHODS OF STUDY 



The satisfactory study of any of the scale insects demands the use 

 of special methods in the preparation of specimens for microscopic ex- 

 amination and such methods are especially useful in the group here under 

 consideration. I feel no hesitation in saying that by far the greater part 

 of the difficulty that has been experienced in dealing with this group has 

 been due solely to the unsatisfactory methods usually employed in the 

 making of microscopic mounts. Satsifactory work can not possibly be 

 done on the basis of tangled masses of antennae, legs and spines, or of 

 specimens so transparent that they can scarcely be located on the slide. 

 Yet it is exactly upon such preparations as these that most of the sys- 

 tematic work on this group has been based. The possession of first-class 

 preparations is as essential for the proper study of these insects as is the 

 possession of a microscope. 



In the past, the difficulty has been due for the most part to the lack 

 of satisfactory methods by which good preparations may be obtained and 

 to some extent to the failure to use those methods which were available. 

 Within recent years the problem has been attacked by various investigators 

 and there no longer exists any excuse for the employment of the crude 

 and unsatisfactory methods with which authors, until very recently, have 

 been content. Green (5), Brain (2), Stafford (10), and Dietz and Mor- 

 rison (3) have all recommended methods, the simplest and least cumber- 

 some of which is perhaps that described by Stafford. This, with certain 

 modifications, is the one which I have employed. 



The general method is simple enough. Specimens may be preserved 

 either dry or in alcohol, preferably the latter, as it is sometimes quite 

 difficult to straighten out individuals which have become wrinkled in dry- 

 ing. The loss of the secretionary covering in the alcohol is a minor point, 

 for the final determination of species cannot be made from this covering 

 and it is usually of incidental assistance only. To prepare the specimens 

 for study they should be boiled in a weak solution of caustic potash. This, 

 for reasons which I shall later explain, should not be more than about 

 an 8% solution. The boiling should be carried merely to the point where 

 the body contents are thoroughly disintegrated, this point usually being 

 reached before the color has been entirely lost. The specimens should 

 then be removed to clean water in a watchglass under a binocular micro- 

 scope (one of the most indispensable aids in procuring first-class prepara- 

 tions), a slit cut in one side of the body and the body contents pressed 



