232 



Mr, Fletcher asked whether Phytonomus nigrirostris had been ob- 

 served as iojurious to clover. He had often taken the larva feeding on 

 clover in different parts of Canada, and in one instance, as recorded in 

 his report for 1884, it was injuriously abundant in Kew Brunswick. * 



Mr. Smith replied that it is also not uncommon on clover in New Jer- 

 sey, but did not do damage enough to attract attention. 



Mr. Gillette said that he had found a small yellow caterpillar in con- 

 siderable numbers on clover, feeding at the base of leaves, in Septem- 

 ber, at Ames, and asked whether any one else had noticed it. 



Mr. Smith said that he had been experimenting for some time with 

 preservative media, looking to some substance which should preserve 

 greens, and general form better than alcohol. He had best success with 

 acetic acid. The histological action of this is to swell the cell and 

 nucleus, and insects preserved in this, extended limbs, antennae, and 

 mouth parts, and left them in excellent condition for examination. In 

 some cases it distorted by extending insects preserved in it. It does 

 not dissolve chlorophyll, but does not prevent bleaching to some ex- 

 tent at least. Reds do not do so well. Mixed with alcohol in equal 

 parts it preserves form perfectly, and in general color also much better 

 than alcohol alone. He has found this the most satisfactory medium 

 thus far used. 



Mr. Howard asked how long specimens had been so preserved and 

 how many times the liquid had been changed. 



Mr. Smith replied that he had none longer than six months, and that 

 there had been no change of liquid. He found this especially useful 

 for aphides, the form of which it preserved perfectly. 



Mr. Woodworth gave as the best preservative process killing in 

 water at 90^ centigrade, leaving from one to five minutes. Then put 

 into alcohol, 35 per cent, one to two hours, 50 per cent, from six to 

 eight hours, 75 per cent, for twenty-four hours or more, and then to ab- 

 solute alcohol. This would usually preserve perfectly, and was a recog- 

 nized process for hardening and preserving for histological purposes. 



Mr. Fletcher asked whether, in the case of large Sphingid larvae, 

 there should be any puncturing of the epidermis to facilitate penetra- 

 tion by the preservative media. 



Mr. Woodworth replied that a certain amount of discretion and judg- 

 ment must be exercised, but that puncturing was not often necessary. 



Mr. Fletcher said that he had taken a lot of ^8^. chersis larvae on ash. 

 They varied remarkably in color and maculation and were blotched and 

 spotted in various ways. He had a fine series of about forty specimens, 

 all different, but that all at the top of the jar were much discolored. 

 They were all right at the bottom, but at the top they became black and 

 discolored. He thinks that discoloration is frequently due to decay of 

 the central portions of large larvae. 



Mr. Forbes said that they use the method described by Mr. Wood- 

 worth in the laboratory, and that they have some very fine specimens. 



