102 TJw Preparation oj Coccldae 



when spreading itself under the cover glass, would disarrange my 

 neatly disposed specimens, and even carry some of them away to the 

 extreme margins. I now prevent this inconvenience by pressing the 

 objects on to the glass with a small piece of thin smooth blotting paper. 

 This absorbs the remaining oil of cloves and makes the objects adhere 

 closely to the glass. Before adding the balsam and cover glass, the 

 mount should be examined for the removal of any small fibres that may 

 have detached themselves from the absorbent paper. Several specimens 

 should be mounted on one slide, some showing the dorsal and others 

 the ventral surface uppermost. 



When dealing with strongly convex species, it is often advisable to 

 slit the dorsum, as otherwise it will not lie flat on the slide. In such 

 cases the venter should be separated from the dorsum and disposed so 

 that the two surfaces can be examined side by side. 



Species that are densely coated with wax, such as Ceroplosfes, should 

 have the waxy covering removed before the insect is boiled in potash. 

 This can usually be done with a fine scalpel, without injuring the insect; 

 or the wax may be dissolved in carbon bisulphide. Boiling in oil of 

 cloves will have the same result. 



The larger species of MonopJilebus and allied genera are often so 

 dense that satisfactory mounts cannot be made of the complete insect. 

 It is better to divide them horizontally, separating the venter from the 

 dorsum completely. If the insects have been preserved in alcohol, 

 this section can be effected before boiling in potash. But, with dried 

 examples, it is necessary to boil them for a short time, until the skin is 

 softened, before attempting the operation. The object is then replaced 

 in the potash and boiled until the two halves come apart and the soft 

 inner tissues separate from the derm, leaving the latter c^uite clean. 



The species of Tachardia (lac insects) are embedded in dense resinous 

 gum which may be softened or completely dissolved by iiumersion in 

 strong alcohol, before treatment. 



Coccidae of the family Diaspidinae are concealed beneath composite 

 scales consisting of the larval exuviae supplemented by secretionary 

 matter. To obtain the insect itself, the scale must be lifted or turned 

 over when the creature will be found either free or lying in the hollow 

 of the overturned scale. If there is any difficulty in extracting the 

 insect, the whole scale may be boiled in potash, when the secretionary 

 matter is decomposed and the insect and pellicles freed. Some of these 

 pellicles should be stained and mounted with the insect itself, as they 

 often afford useful characters for the differentiation of closely allied 



