[Vor. 1 
254 ANNALS OF THE MISSOURI BOTANICAL GARDEN 
The wood of the lilac is white in color, hard, and close-grained. 
In younger trunks there is no appreciable difference between 
heart-wood and sap-wood; as the trunks grow older, however, 
the heart-wood turns darker, and in those twelve years old, or 
thereabouts, it is distinetly darker than the rather thin,white sap- 
wood. 
The disease first manifests itself in the inner heart-wood, 
frequently in close proximity to the holes made by the lilac 
borer. This lepidopterous insect (Podosesia syringe Harris) 
(for whose identification I am indebted to Dr. E. P. Felt) has 
been found very destructive to lilac bushes, and, according to 
Beutenmüller (1), occurs from New England and the middle 
states westward to Colorado and southwest to Texas. Quoting 
from Beutenmüller's account: “Тһе female deposits her eggs 
in patches on roughened or knotty places on the bark of ash and 
lilac. The eggs, according to Hulst, hatch in about six days, 
and the newly born larve at once eat their way through the 
bark into the solid wood. They run their channels longitudi- 
nally for about 8-10 inches through the wood. The larve 
pupate in slight cocoons after cutting their way to the bark, of 
which they leave only a thin outer skin. The pupation usually 
takes place early in May, and the moths emerge in about three 
weeks." Felt (2) briefly described the habits of the larva, 
stating that ‘‘a sign of its presence in midsummer being largely 
the sudden wilting of a shoot." He quotes from an observation 
made by Dr. Kellicott in which the latter states that he “watched 
20 or more issue from a single tree in one day, and found that 
often there were more than one hundred in one tree." Felt 
recommends cutting and burning all infested wood in the early 
spring. 
In the vicinity of St. Louis the lilac borer has been very active 
in recent years, judging from the fact that very few lilac bushes 
over five years old were found free from its attacks. Without 
much doubt the fungous spores get into the interior of the lilac 
trunks through the borer holes, and start to develop within the 
heart-wood on the edges of the borer holes. In pl. 9 fig. 1 two 
borer holes, still filled with pieces of the borings, can be seen in 
the lower right-hand trunk, and one small hole in this same sec- 
tion occurs in the sap-wood. The fungus, after it has begun to 
