K. i:. Gkeen * 103 



species. In the absence of male puparia it is often difficult to decide 

 whether a certain species should be included in the genus Aspidiotus 

 or Diaspis. Examination of the larval and nymphal pellicles of the 

 female will usually decide this point, for in Aspidiotus the dorsal half 

 only of the pellicle is present in the scale, whereas in Diaspis the venter 

 remains attached and will be found beneath the posterior extremity of 

 the peUicle. 



In the genera Aonidia, Fiorinia and Leucaspis, the adult female is 

 completely enclosed within the nymphal pellicle, and it will be necessary 

 to break this open (with a fine needle) to obtain the actual insect. 



Insects of the genus Asterolecanium require very careful handling. 

 The derm is exceedingly thin and delicate. A very short immersion 

 in boihng potash is sufficient to soften the tissues and decompose the 

 contents of the body. I find it best to place the complete scale in the 

 potash and continue the boiling only until the secretionary matter is 

 dissolved, when the insect — now freed from its covering — should be 

 immediately transferred to distilled water. 



The treatment must be modified when deahng with adult males of 

 any of the smaller species. Boiling in potash results in the hopeless 

 crumpling of the wings and their entanglement with the other limbs. 

 For such deHcate objects a more prolonged immersion in cold potassium 

 hydrate is preferable. 



The procedure may be roughly summarised as follows : 



(1) Boil in potash for a few minutes, or immerse in cold potash 

 for a longer period, until the contents of the body are completely 

 softened. 



(2) Soak in distilled water for 24 hours. 



(3) Press out the softened contents, and clean the surface parts. 



(4) Mount temporarily in dilute glycerine. 



(5) Stain with fuchsin, for 24 hours. 



(6) Fix stain with picric acid for 5 or 10 minutes. 



(7) Wash and remove superfluous stain in 70 % alcohol 



(8) Wash in absolute alcohol. 



(9) Place in oil of cloves for 10 minutes. 

 (10) Mount finally in canada balsam. 



