138 
Journal of Agricultural Research 
Vol. XXI, No. 3 
NATURAL ENEMIES 
In connection with the work on this species, the following io species 
of hymenopterous parasites have been reared from prepupal larvae: 
Apanteles n. sp. 
Angitia sp. 
Aethecerus n. sp. 
Scambus sp. 
Epiurus sp. 
Euteles n. sp_ 
Habrocytus n. sp 
Copidosoma sp.. 
Elachertus sp.... 
Eulophid. 
. Det. C. N. Muesebeck 
Det. R. A. Cushman 
Det. R. A. Cushman 
Det. R. A. Cushman 
Det. R. A. Cushman 
Det. S. A. Rohwer 
Det. S. A. Rohwer 
Det. A. B. Gahan 
Det. A. B. Gahan 
Det. A. B. Gahan 
Of these parasites the Copidosoma and the Euteles are most abundant. 
In 1919 the writer obtained only the following: Euteles n. sp., Copi¬ 
dosoma sp., Epiurus sp., Aethecerus n. sp., Apanteles n. sp., Habrocytus 
n. sp., and the eulophid. In this year 234 of the 1,886 host larvae 
examined were parasitized; thus the seven species listed above produced 
in this year a parasitism of approximately 12 per cent. 
In addition to the foregoing insect enemies there is a small bird known 
locally as the “pine siskin” that in a few instances has been observed 
feeding on the adults during the flight period. 
LARVAL MORTALITY 
During the studies in the spring of 1919 a number of mature larvae were 
collected to determine the relative mortality in this stage. Mortality 
during this stage only was studied, as it was practically impossible to 
obtain field data of this character for any other stage. A total of 1,886 
larvae were examined; of this number 178, or 9 per cent, were dead and 
more or less withered. The cause of this mortality was not determined, 
though it is probably a bacterial disease. 
DISTRIBUTION 
The distribution of the lodgepole pine needle-miner in the Yosemite 
National Park is confined to the lodgepole pine stands in the higher 
elevations north of the Merced Canyon. The extent of this distribution 
is shown on the map (fig. 4). 
One striking feature of its distribution is its occurrence only in dis¬ 
tinct zones or areas of epidemic infestation. Within these areas the in¬ 
festation is abundant, involving every tree with resultant severe damage 
to the entire stand. Outside of the infested areas the insect does not 
occur in the larval stage at all, or in such minor degree that no trace 
of it can be found. Only along the borders of the infested areas have 
trees been found which contain only a low percentage of affected needles. 
These areas of epidemic infestations occur only in belts between two 
fairly definite contours of elevation. The larval infestation has not 
