266 Transactions of the 



between Figs. 28 and 29, partaking of both. Of course the repre- 

 sentation was too rude to positively assert that the beaded structure 

 of the insect scale arises from interference and diffraction, &c. ; but 

 it has its value as bearing on the opinions and figures contained 

 in this imperfect sketch. 



Photography would have been used more largely, had I not learnt 

 from experience that some of the appearances would not have been 

 easy to record without very considerable trouble, especially as the 

 season was not sufficiently advanced to undertake the experiment 

 with either comfort or certainty. 



Every care has been taken to render the objects as seen, but to 

 obtain the prismatic effects with all their charm and vigour was 

 hopeless. To quote Mr. Slack's words, "It is only by combining 

 all the appearances which seem to give real information, that we can 

 expect to arrive at a true conception of structure;" as aids there- 

 fore to others, rather than as dogmatic assertions, it is hoped the 

 foregoing remarks will be received by the Fellows of the Society, 

 to whom I beg to ofier every apology for such " dry as dust " de- 

 tails, in venturing to attempt some explanation of the wondrous 

 contrivances, endowed by the Creator with the property that sheds 

 a lustre, both on the gay and gaudy visitor of the hour, or the 

 silent and agile tenant of the dreary cellar. 



