( Ivii ) 



is their shrivelling. You will remember that I suggested 

 drying these in partial vacuum of an air-pump ; but though 

 I believe this plan would be a good one, I have never tried it. 

 I found in New York that the cheapest air-pump would cost 

 four or five guineas, and 1 did not feel justified in going to so 

 much expense merely for an experiment ; still, if you wish 

 me to try it, you might send me a cheap air-pump from 

 England ; the flies in question are quite numerous, and the 

 air-pump plan might do also for Psocidce, May-flies, &c. You 

 can tell better than I whether the experiment is worth the 

 expense ; any air-pump that would exhaust half or two-thirds 

 of the air ought to do. 



'* 10. Cympida. — I am getting many of these, but they are 

 generally studied in connection with their galls. I will do 

 what I can to breed them, but doubt if I should spend much 

 time on it. The species appear to be quite numerous. I 

 should also do what I can in breeding the Lepidoptera, as it 

 really seems the only way of collecting them here. The real 

 trouble, I think, is the wind ; a calm night is almost a phe- 

 nomenon here ; the valleys, which elsewhere are the best 

 places for moths, are here so many troughs for the land- and 

 sea-breezes ; I do not mean to say that I am getting no 

 Lepidoptera, but the collection works up very slowly. To 

 complete the collection of plants, I want to do what I can in the 

 lower forms ; and I once more beg that you will ask the Kew 

 naturalists for information on this subject. I have already 

 made a start with the Mosses, but am puzzled about the 

 Fungi and Lichens. How can the Lichens be separated from 

 rocks and preserved ? As for Fungi, some kinds can readily 

 be dried ; should the others be preserved in alcohol ? Finally, 

 I might with very little trouble make valuable collections of 

 Desmids and Diatoms, but should the Confervic containing 

 them be preserved dry, or in alcohol ? Of course I do not 

 expect to spend any time on these things, but it is so easy to 

 get a little mud or moss now and then, and these may prove 

 rich mines for microscopists. Please do not think that in 

 mentioning all these things I am proposing to myself more 

 work than I am able to do. All the groups I have mentioned 

 would not increase my work very materially, but, with them, 



