190 PROCEEDINGS OF THE ACADEMY OF [1883. 



September 4. 



Mr. Thos. Meehan, Vice-President, in the chair. 



Sixteen persons present. 



The death of John C. Dawson, a member, Avas announced. 



Exudation from Floioers in Relation to Honey-dew. — Mr. Thos. 

 Meehan remarked that our standard literature 3^et continued to 

 teach that the sweet varnish-like covering often found over every 

 leaf on large trees, as well as on comparatively small bushes, was 

 the work of insects, notably Aphides. So far as he knew, Dr. 

 Hoffman, of Giessen, who in 1876 published a paper on the subject, 

 is the only scientific man of note who takes ground against this 

 view. He met with a camelia without blossoms, and wholly free 

 from insects, and yet the leaves were coated with "honey-dew," 

 as it is generally known. He found this substance to consist of a 

 sticky colorless liquid, having a sweetish taste, and principally gum. 

 Mr. Meehan said he had often met with cases where no insects 

 could be found, as well as others where insects were numerous, 

 and where in the latter case, the attending circumstances were 

 strongl^'^ in favor of the conclusion that the liquid covering was 

 the work of insects. 



He said he believed that few scientific men had any knowledge 

 of the enormous amount of liquid exuded by flowers at the time 

 of opening, and he had seen cases where the leaves were as com- 

 pletely covered by the liquid from the flowers, as if it had exuded 

 from the leaves, as he believed Dr. Hoffman had good grounds for 

 believing is often the case. He had already biought to the atten- 

 tion of the Academy cases where, large quantities of liquid had 

 dropped from the flowers to the leaves below, of which Yvcca^ 

 Mahonia and some others had been recorded in the Proceedings 

 of the Academy. Akebia had been noted by Mr. Wm. M. Canby to 

 drop from the leaves at certain times, and Sach notes in his Text- 

 book the moisture which fills the small flowers of Thuja. In 

 connection with the last case, the exudation from Coniferae, he 

 met with a remarkable case during his recent journey through the 

 northwest coast. While collecting plants along the east shore of 

 the Columbia River he noticed a plant of .4Z???/.s- Oregana, covered 

 with honey-dew. The woolly Aphis, so well known for its pref- 

 erence for alder, also abounded. Little drops of liquid were in 

 many cases attached to the apex of the abdomen, and ti>e conclu- 

 sion was reached that in this case at least, the probabilities favored 

 the insect origin of the liquid on the leaves. Proceeding a few 

 feet further, towards the trunk of a large spreadiiig Sitka spruce 

 {Abies Sitkensis)^ and then on the other side, a bush of -P//?v/.s 

 rivularis was observed also covered, but not a sign of an insect 



