No. 406.] GALL OF THE MONTEREY PINE. 805 
the normal leaf bundles, or fascicles, is increasingly marked. 
By the first of May the normal leaf bundles are about 3 cm. 
long, and the galled ones from 1 to 1.5 cm. 
in length. In addition to the difference in 
length, the bases of the latter are much swol- 
len, and many of the leaves cease to grow in 
length, although the diameter of their bases 
continues to increase until autumn (Fig. 4). 
To learn what plant tissues 
were affected, and in what man- 
ner, so that some conclusion might 
be drawn as to the immediate 
cause of the hypertrophy, there 
were selected for more careful ; 
study leaf bundles taken in April Pel raid a 
— the season of great changes DaT 
hades ann; and development in the leaf bun- 
Hi Jair, Natu- dle. All of the material was fixed in hot alcoholic 
t corrosive sublimate, a saturated solution in 30 
per cent alcohol being used. 
If a galled leaf bundle is examined in the middle of April 
or the first of May, the cavities in which the larve lie will be 
A genes 
A 
( 
Se 
X 
b 
— 7 5 
ae f 
Fic. s. — Showing the development of the protuberances which — = upper part of the 
larval cavity: 4, May 1; B, July 15; C, mature, a autumn (7, c, scale; X, devel- 
opment of protuberances and larval cavity). 
found almost completely developed. The cavity is in the axil 
of the leaf and is nearly covered above and on the sides by 
