Chapter XIX. 
INSECTS INJURIOUS TO THE JUNIPER. 
Insects Injurious to the Tree-Juniper. 
Juniptru* cirginiana. 
AFFECTING THE TRUNK. 
1. The juniper bark-borer. 
Phl(F08inu8 dentatus (Say). 
Order Coleoptera ; family Scolytid^e. 
Making a short straight primary gallery, with about 15 to 50 longer secondary gal- 
leries branching from it at nearly right angles, often ending in round holes perforating 
the bark ; a small white curved grub, changing to a light brown cylindrical beetle. 
We have observed the depredations of this common beetle on the 
junipers about the city of Providence. The attacks were confined to 
sickly or dead trees ; whether the cause of death was due to the attacks 
of this beetle or not could not be ascertained. The beetles were found 
May 2 and 13 alive in the burrows, which also contained the fully grown 
larva?, but no pupa? w ere observed. In one fallen juniper tree, the 
trunk of which was about 5 inches in diameter, the mines were unu- 
sually close together and abundant, fifteen occurring on one side of the 
trunk in a space about one foot long. Selecting a separate average 
mine for description, such as is figured in the accompanying engraving, 
the main or primary gallery is 18 mm to 25 mra (1J to 2J inches) long and 3 mm 
wide, wideniug at one end into a trilobed chamber twice as wide as the 
main gallery. In a gallery 25 mm long, including the three-lobed cell, from 
which no lateral or secondary galleries proceeded, there were forty-eight 
secondary galleries on one side and fifty-one on the other, the mouths 
of the opposing tunnels being alternately arranged. The secondary 
galleries being a little less than one-half millimeter in width ; those 
arising at each end of the primary gallery are 4:5 mm long; those arising 
near the middle from one-third to one-half and two-thirds as long; the 
ends of the tunnels are about \5 mm in width, and they often communi- 
cate with the hole made by the insect for its exit through the bark, 
which is 1.5 ram or a little less. These holes are indicated by the round 
904 
