58 



done to foliage, and we can but think that the flies occurred on plants 

 that had been previously eaten by some other insects and that the work 

 was erroneously attributed to these Bibios when they appeared in such 

 numbers. 



Plant-lice were very abundant on almost all kinds of plants, and 

 especially on plum trees did a great deal of damage. The species 

 known as Aphis prunifolii was one of the most abundant forms, but 

 other species occurred, and one which was apparently the most common 

 and destructive appears to be referable to Myzus persicce. This is a 

 brown or reddish-brown species, with greenish legs, and it occurs in 

 great abundance on the terminal portions of the twigs and causes very 

 extensive curling and twisting of the leaves, being almost as bad as 

 some gall-forming species in the amount of distortion produced. On 

 this account it is more difficult to destroy with kerosene emulsion than 

 the forms that are less protected, and we found that in some cases the 

 only satisfactory method of reaching them was to dip the worst branches 

 directly into the emulsion and wash them about till all the corners and 

 cavities had been reached. Later in the season the parasitic insects 

 affecting these lice became abundant and their injuries were practically 

 stopped. They can most seriously affect the growth of the fruit as 

 well as the general health of the tree. On a small tree upon which I 

 allowed them to develop for the purpose of watching their progress, 

 they clustered on the stems of the plums, and even on the plums them- 

 selves, and the fruit thus infested became much wilted, much of it 

 covered with exuded juices; and even after the lice had been destroyed 

 by parasites failed to recover and make a good growth, some attained 

 only about half size, and were tough and of poorest quality when 

 ripened, while a portion became so withered that they failed to ripen 

 at all. It is evident that the insect should be attended to early in 

 spring, before the lice become numerous and the leaves become curled, 

 as then they can be destroyed very much easier and it will prevent the 

 damage to the fruit. 



Two other forms, apparently distinct species and quite different also 

 from Phorodon humuli, were observed in small numbers on wild plums, 

 but they have not as yet been referred to any described species. 



The Wheat Plant-louse (Siphonophora avenue), which has been abun- 

 dant in States east of here for a few years past, appeared in abundance 

 in the eastern part of the State this season, especially in the north- 

 eastern portion (Jackson and adjoining counties). It seems to have 

 been noticed first only a few weeks before ripening of grain, and for 

 two or three weeks I received a great number of samples. In almost 

 every case, however, the specimens sent were noticed to be in large part 

 affected with parasites, and I could reply that the injury from the lice 

 would probably soon cease. In all cases where I received a second 

 notice from the same place it was to the effect that the parasites had 

 been increasing and that the injury had ceased. The louse is evidently 



