1919 ENTOMOLOGICAL SOCIETY. 29 



in diseases of the chest, and it has also been chiimed to cure certain affections 

 of the eyes. In Italy it has been used as a salve for the treatment of wounds 

 and sores. 



Honeydew is gathered and stored in large quantities by bees at certain 

 seasons of the year when the nectar flow is low. While this is a disadvantage to the 

 beekeeper in that he can not dispose of it, under the present laws, as pure honey 

 it has the advantage of making available, with little expense,, large quantities 

 of honeydew. At present in this country the honeydew thus secured is nearly 

 all used by our bakers in the making of cakes, etc. It is, however, a source 

 of some of our rare laboratory compounds, and no doubt in the future will be 

 used in the manufacture of products formerly imported at a high price, for it is 

 available in large amounts. It is interesting to note that the cornicles were so 

 long associated with honeydew. Morren^ even claimed that they were employed 

 in giving nourishment to the newly born young much in the way that the mammary 

 glands supply nourishment to young mammals. 



In recent years aphids have been associated with the transmission of im- 

 portant plant diseases. Prof. D. H. Jones- early indicated by his experiments 

 that aphids are one of the factors in the transmission of pear blight. In connec- 

 tion with disease like mosaic and spinach-blight apids have been credited with 

 an important role but the study of the relation of these insects to plant diseases is 

 cis yet in its infancy. 



It is claimed by some workers that large numbers of certain aphid species 

 on forage plants are responsible for the injuring of cattle. In China and other 

 eastern countries, on the other hand, some of the galls have been employed as 

 food and as native medicines. In metlieine they are employed chiefly as astringents, 

 although they have also been used in other ways. 



The relations between ants and aphids have been a favorite subject of study. 

 In return for the honeydew many ants take great care of aphid colonies, building 

 shelters for them, protecting them from their enemies and transferring them 

 when necessary to new feeding grounds. Some even carry the young above 

 ground during the warm sunny hours in spring and return them to their nests 

 for the night. The writer has supplied ants with several hundred wingless aphids 

 and watched these insects distribute them over the most tender feeding areas of 

 a young tree there to start new colonies. 



The peculiar habits of the species afford a field of study paralleled in few 

 other groups. Alternation of hosts is commonly met with, and this habit adds 

 to the difficulty of tracing life cycles. Some species on their primary hosts 

 are remarkably different in structure from the same species on their alternate hosts. 

 The writer has found that if species can be made to live on one host, forms 

 which normally show characters associated with a secondary host will develop the 

 characters, in part at least, of the forms occurring on the primary host. Thus 

 races may be reared which have a definite relation to a given host and quite a 

 definite structure. In some cases these races become more or less fixed after long 

 periods, and it is with the greatest difficulty that they are again established on 

 their original hosts. When this is done they ultimately reassume the characters 

 associated with their original hosts. 



The presence of winged and Avingless forms has given rise to studies on wing 

 production. This subject has been attacked from several standpoints. The 



^ Morren, Chas. — Ann. des Sciences Nat., 1836. 

 = Jones, D. H.— Bull. Ont. Agr. Coll. 



