262 



wandering far from the mother aphis, unless crowded for room, when 

 they move away to a place where they will not be interfered with, 

 which may be lower down the stem, on the under side of the leaf, or 

 upon a new plant. It can readily be seen from the figures above that 

 the number of lice upon a plant, which has been neglected for two 

 or three weeks, will be something enormous, even with but one fe- 

 male on the plant to start with. Winged females are produced at 

 intervals, and these fly to other plants and bring forth young in the 

 same manner as the wingless form, that is, without the intervention 

 of the egg state. It is not known how long this reproduction of the 

 species agamically can continue under greenhouse conditions, but it 

 is certain that a sexual form of female is produced at intervals which, 

 after mating with the males, produces eggs from which agamic fe- 

 males again appear, and give birth to living young. 



So far as known to the writer, this species attacks no other plant 

 than the chrysanthemum. Other species of black aphids occur in 

 conservatories, notably upon the rose and violet, which are often mis- 

 taken for this one, but which are distinct species. (Bui. 119, Md. 

 E. S.) 



The Green Aphis of the Rose. The green aphis of the rose is 

 one of the greatest drawbacks to successful rose culture in green- 

 houses. It is found attacking the leaves and young twigs wherever 

 the rose is grown, and occasions the florists considerable expense and 

 labor in its control. The species was originally described from Eu- 

 rope. Some doubt exists as to whether the European species and our 

 own are identical, but most writers who have treated the subject have 

 considered them as the same. 



The winged form is rarely seen, practically all reproduction 

 being carried on by the viviparous form. Breeding in this form is 

 extremely rapid, one female producing from four to ten young per 

 day, and it requiring but eight days to two weeks for these young to 

 reach maturity. It is surprising how soon plants will become rein- 

 fested after a fumigation that apparently killed all but a few scatter- 

 ing individuals. Three or four weeks suffice to reinfest them almost 

 or quite as bad as before the fumigation. The favorite part of the 

 plant for these aphids to feed upon seems to be the extreme ends of 

 the new growth or the flower buds. They not infrequently become 

 so thick about the buds as almost to cover them, and when this occurs 

 the bud is rendered worthless. In most of the essential points of its 

 life history this species closely resembles the chrysanthemum aphis. 

 -(Bui. 119, Md. E. S.) 



The Melon Aphis. This plant louse is a well-known enemy 

 of outdoor grown plants, especially those belonging to the Cucur- 

 bitaceae, and has been mentioned frequently as a pest of greenhouses 

 as well. It is a general feeder, affecting many weeds and garden 

 vegetables, besides the Cucurbits. In greenhouses the writer has 

 found it only upon cucumbers, begonias and an Hibiscus, but it 

 doubtless affects many others also. Like other similar species it is 

 known to florists and gardeners as "green fly," no attempt being 

 made to differentiate between it and other greenish-colored species of 



