COLLECTING AND PRESERVING COCCID^E. 49 



(e) Soak in oil of cloves until all trace of air has 

 disappeared, and finally mount in Canada balsam in 

 xylol. 



Should the oil not penetrate the specimens, gently 

 heat it, together with the specimens, over a spirit lamp. 

 The specimens will readily clear by this process, and it 

 entirely prevents fogged mounts. 



Should air-bubbles occur in the specimen after mount- 

 ing in Canada balsam, place the mount over the gentle 

 heat of a spirit lamp. It is advisable, however, not to 

 apply heat except in extreme cases, as it destroys the 

 stain, and sometimes shrivels the delicate parts of the 

 insect. 



The foregoing will serve equally well for all stages 

 of the insects; but for fresh examples of the males, 

 soaking in cold potash will sometimes give better re- 

 sults. Staining brings out the minute detail in a way 

 that nothing else can ; and I must here acknowledge 

 my indebtedness to my friend and co-worker Mr. E. E. 

 Green, of Ceylon, for the discovery of such an excellent 

 staining medium as Crawshaw's magenta; without its 

 aid it is well-nigh impossible to trace the minute but all- 

 important structural details. The density of the stain 

 may be regulated in the final washing of the alcohol. 



There is yet another method of preparing the Coccidas 

 for museums, and this by making up life-history cases 

 of injurious, beneficial, and mimetic species. Of the 

 first we have at least four indigenous species in- 

 jurious to fruit crops, viz. Aspidiotus ostre&formis, 

 Curtis; Mytilaxpis pomorum, Bouche; Pulvinaria 

 ribesise, Signoret ; and Lecanium cori/li, Linn. And 

 there are only too many species injurious to our stove 

 and greenhouse plants which could be worked out in 

 the same way. The beneficial species of importance 

 are Coccus cacti, Linn. ; Tachardia (Carteria) lacca, 

 Kerr ; and Ericerus Pe-la, West. It may be well to 

 add that at the Liverpool Museum there are very 

 interesting life-history cases of the two former species 

 mounted together with personal ornaments, etc., made 



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