43 



1893 (or '4) Messrs. Galloway and Dorsett, at that time jointly con- 

 cerned in the projjagation of violets at Garrett Park, Md., noticed 

 for the first time a darker species of plant-louse in their greenhouses, 

 which in time practically dis]3laccd the other form and has become 

 the most injurious violet pest of this vicinity and in other localities 

 where it has been introduced. The matter was not immediately brought 

 to the attention of any specialist in the Aphidida^ and the species was 

 not identified until recently, even generically. What is with little 

 doubt the same insect is now known to be widely distributed in our 

 violet-growing regions, being generally recognized b}" the trade under 

 the rather inappropriate name of "black aphis" or "black fly," by 

 which cognomens it has received mention in recent yeai's in various 

 floral journals. Regarding its rank as a pest, Mr. George Saltford, a 

 prominent violet grower of Hhinebeck, N. Y., says: "It is the great- 

 est scourge of the violet grower to-day." (The Florists' Exchange for 

 December 10, 1808.) 



NATURE OF INJURY. 



These plant-lice are to ])e found in greatest numbers at the crown 

 of the violet plant, in the petioles and on the under side of the leaves, 

 and they accomplish considerable injury by entering the young open- 

 ing buds and inserting their haustella, or sucking tubes, through the 

 overlapping petals. When the petals unfold they are seen to be dis- 

 torted and bleached where they have been injured, these spots show 

 ing greenish-white, and in some cases almost pure white. The flowers 

 also are dwarfed and distorted, the stems are nearly always shorter 

 than is normal, and the flowers altogether present a weak, sickly, and 

 unsightly appearance when contrasted with healthy blooms. Injury 

 is apt to be very disastrous unless the aphides are destroyed in some 

 manner. In the accompanying illustration (Plate II) normal violets are 

 shown below, and a small luinch of flowers injured by this aphis are 

 illustrated above. 



This species of aphis has not been under continued observation, and 

 hence we have no verj^ full notes regarding its development. Winged 

 forms were noticed in March, April, and May, and again during the 

 first two weeks of November. 



DESCRIPTIVE. 



As the species was apparently undescribed, a description was drawn 

 up by Mr. Th. Pergande and pul)lished in the Canadian Entomologist 

 of February, 1900 (Vol. XXXII, pp. 29, 30). The grower of violets will 

 readily distinguish this from the green aphides which affect his plants, 

 with the aid of the accompanying illustration (fig. 15). The winged 

 female, shown atr/, is of atti'activo appearance. She has a dark cherry 

 or purplish brown body, clear wings with the veins strongly and con- 



