400 PRESERVATION OF INSECTS. 



that the superfluous moisture may fly off, before 

 finally closing the case. If this be omitted, the 

 inner surface of the glass will sometimes become 

 partially obscured by the fume arising from the 

 mixture. The experienced entomologist needs not 

 a notice like this ; but the young collector probably 

 will not regard it as unnecessary information, and 

 may be spared by it from both mortification and 

 regret. I have known insects commence their 

 serious operations before the collections of the sum- 

 mer could be arranged in their permanent cases. 



In noticing above, that this solution is generally 

 harmless, it is requisite that mention should be 

 made of the few instances in which it has been 

 observed to be injurious. I have applied it to 

 many specimens of foreign and British insects, and 

 commonly observed no indication of its having 

 been used, when the creatures had become dry. 

 But to confine our attentions to English specimens, 

 when the solution is made stronger than recom- 

 mended, it will, after a time, injure the fine yellow 

 of the sulphur butterfly (papilio rhamni), by turn- 

 ing parts of it brown and dirty ; but even in its 

 reduced state it has a manifest effect upon the 

 colours of two of our moths, the Dartford emerald 

 (phalana lucidata), and what is commonly called 

 the green housewife moth (phalana vernaria), 

 changing their plumage in several places to a red 

 buffy hue, when at the same time the beautiful 

 green wings of the small oak moth (phalana mri- 

 dana) are in no way altered by it. But notwith- 



