14 



ment and fast having whetted their appetites and rendered them ex- 

 ceedingly active in their visits to the flowers. This is strikingly il- 

 lustrated by the fact that 1877, which was cold, damp and rainv, but 

 besprinkled with quiet, warm days, was not less productive of obser- 

 vations than the preceding summer, when, for weeks together, there 

 was scarcely a cloud overhead. So while one day there may not be 

 an insect visible, the next may witness them in such abundance that, 

 as the writer expresses it, one could wish for tw'enty eyes and hands 

 that nothing might escape him. 



From a table showing the abundance and activity of the different 

 orders of insects, it appears that in ascending the mountains the rela- 

 tive number of Coleoptera and Hymenoptera decreases, while that of 

 Diptera and Lepidoptera increases. Thus, in the lowlands, of every 

 TOO flower-visitmg msects, 15.3 are Coleoptera, and 30 Diptera, 

 while 43.6 are Hymenoptera, and but 9.3 Lepidoptera;' but above the 

 timber line, with 6.8 per cent, of Coleoptera, we have 43.6 per cent. 

 Uiptera, and with 18.3 per cent, of Hymenoptera, 30.7 per cent, of 

 Lepidoptera. I'his renders intelligible the great abundance of narrow 

 and partly-closed flowers, and of those which, like many species of 

 ^axifraga and Veronica, are especially attractive to Syrphidae and 

 other Diptera; whereas, without a knowledge of the relative dis- 

 tribution of the flower-frequenting insects it would be a hopeless rid- 

 dle. ^ 



r -^ 



The author has followed the excellent plan, adopted in his earlier 

 book, of compihng a systematic index to the insects observed, con- 

 necting with each species the flower it frequents and the degree of 

 their adaptive development. It is to be regretted, however, that, in 

 the alphabetical index to the plants observed, he refers only to the 

 page on which their flowers are described and their visitors noted, and 

 not to the places where they receive mention in the chapters devoted 

 to generahzation and conclusions, since numerous biological notes of 

 value occur in these latter places. 



Cambridge, Mass., Jan. 11, iSSr. William Trelease 



O 



15. The Preservation of Pileate Fungi for the Herbarium — 



As well known to those who have studiedThe Fungi and have had some 

 experience in attempting to preserve them for purposes of future ref- 

 erence, the most difficult kinds to manage are the fleshy pileate 

 species commonly called " toadstools." . A great number of ex- 

 periments have been made from time to time with a view to dis- 

 cover some plan by means of which the forms and colors of these 



nWnn'^ ^r^' ^>^^1\ ^'^^ '>'" °f °^h^^ cryptogams and the 

 phaenogams be retained for an indefinite period ; but the results at- 



Dr"'t n"' w^r •''' ^"""^^^ ^^-^^ ^'^P^^t^ satisfactory. In 1 794, 

 nnnJ! T Withering communicated to the Tramactions of the 

 Linnaean Society (Vol. up. 263) a paper entitled "A new Method 

 of Preserving Fung.," and m which he recommends that the specimen 

 be immersed temporarily in a "pickle" consisting of an ?queTs 

 solution of su phate copper or of acetate of zinc, and af^^rwards be 



mTxed wk 'a :^l;r ^^^^•^-^-^^"y-/-/^d glass jars filled with water 

 mixed with a small percentage of alcohol. In the first volume of 



