ee 
Each maggot furnishes subsistence for but a single parasite. Adults 
were bred from resin masses of both the hemlock and the lowland fir 
bark maggots. 
Eutelus flavipes Walk. is one of the small chalcidid flies. The 
females have dark metallic-green bodies, cherry eyes, light brown legs, 
rather dark antenne, and are about 0.12 inch in length. The males 
are smaller, about 0.08 inch long, and have a broad yellow band across 
the abdomen. Their bodies are a lighter green and the legs and anten- 
ne are yellow. Each maggot supports a number of parasites, usually 
about a dozen. The pups are formed in the body of the host in the 
outer resin mass. The adults emerge during the latter part of June. 
This species was bred only from the hemlock resin masses. 
These two parasites were the only natural enemies found. There was 
no evidence of any bacterial or fungous disease, and the maggot is so 
concealed in the bark and resin that it is well protected from preda- 
ceous enemies. 
ASSOCIATES. 
Two small pill beetles (Amphicyrta simplicipes Mann. and Simplocaria 
nitida Mots.) were frequently found on and near the resin masses. Their 
relation, if any, to the syrphid was not determined. 
METHODS OF PREVENTING LOSSES. 
Since the black check is the result of the work of the insects during 
past years, or even centuries, and is thus distributed all through the 
wood of the trunks of the matured affected trees, the only methods 
which appear to be available for preventing losses are: 
(1) Where clear stuff is required, select timber which, as indicated 
by the absence of the old resin masses on the bark, is free from the 
trouble. 
(2) Utilize timber from badly affected trees for box material and 
other purposes where the checks are not objectionable. 
(3) Utilize the bird’s-eye or curled wood for natural-wood finish. 
BARK MAGGOTS IN OTHER TREES. 
THE LOWLAND FIR BARK MAGGOT. 
In 1903, while studying the black check of the hemlock at Satsop, 
Wash., a similar trouble was discovered in the white or lowland fir. 
The insect causing it was reared and proved to be Chetlosia hoodianus 
Bigot, a species closely related to the hemlock fly. The maggot is very 
similar in size, appearance, and habits. The adult is a trifle larger and 
not so dark in color. The thorax is dark brown, and the abdomen a 
light chocolate. The emergence of the adult takes place a little later 
in the season than that of the hemlock species. Most of those reared 
emerged about the middle of May, but the last one did not come out 
of the resin mass until August 12. 
