118 [A8SEMBLY 



Mr. Wm. Trelease, a botanist of note, referring to honey-dew as 

 sometimes secreted by aphides, adds: " But in some cases this sub- 

 stance is an excretion from the leaves, apparently due either to the 

 climatic conditions obtaining at the time, or to a diseased state of 

 the plant. Small glands are found at the tips of the serrations on 

 the leaves of many plants, and some of these produce a plentiful 

 supply of nectar." {Report of Cotton Insects^ 1876, p. 326.) 



[Note. — Appended to the above, November 28, 1887. — Since the above 

 was written, the life-history of this interesting insect has been worked out, com 

 pletety, it is claimed, by Prof. Riley, Chief of the Entomological Division 

 at Washington, and the assistants under his direction. The following is a brief 

 summary : The eggs are deposited on the twigs of plum trees in the autumn 

 (October). They hatch at the putting out of the leaves the following spring. 

 Three generations follow on the plum, of which the last only is winged, which 

 at once migrates to the hop-yards. The fourth and succeeding generations on 

 the hop to the eleventh inclusive, are wingless females. The twelfth genera 

 tion consists of winged males and females — the latter, agamic, and these return 

 to plum trees in September. Here, the thirteenth generation is composed of 

 sexual wingless females, which, after mating, deposit the eggs which are to 

 hatch the following spring in continuation of the species. For a detailed state- 

 ment of the above see a communication made by Mr. L. O. Howard, of the 

 Division of Entomology, under instructions from Prof. Riley, in the 

 Gountry Gentleman, for November 17, 1887, p. 875, giving also, the latest studies 

 of Prof. Riley upon the insect, made in England during the present autumn. 



The Apple-tree Aphis. 



Aphis mali Linn. 



The unusual abundance of this insect the present year, as pre- 

 viously noticed, brought with it from many localities in the Middle 

 and Eastern States inquiries of its character and how it best could 

 be destro3 r ed. To an inquiry from St. Albans, Yt., accompanied 

 with specimens which the writer had never seen before, which 

 an old tree-pruner could not tell what they were, and which were 

 represented as having been at first observed on the leaf-buds but 

 were then traveling over the trees — reply was made through the 

 New England Homestead, as follows : 



The insects infesting the apple trees are the common apple-tree 

 aphis, sometimes popularly known as the apple-louse. They belong 

 to a class of insects named aphides or plant-lice and have long been 



