As soon as the maggot leaves the inner chamber the irritation ceases 
and the wound begins to heal. The cambium grows down into it year 
after year, and the annual growth of wood formed there slowly covers 
it over until in three or four years it is completely buried (fig. 5) 
beneath the new growth and thus forms the black check. 
As the wood grows down into the wound in healing it over, a depres- 
sion is formed in each new layer, but sometimes the new layer thickens 
around the depression and forms an elevation above the surrounding 
surface. In both cases an ornamental curl is formed that will show as 
a bird’s-eye effect in bastard-sawn or longitudinal sections of the wood. 












































Fra. 5.—a, Longitudinal section of wood containing a black check; b, the check; ec, the stain in 
the wood beneath it; d, the curls in the wood covering it; e, the resin mass on and in the bark; 
f, section a split into four sections to show tangential views: g, tangential view of check. 
hh, tangential view of curls; 7, black spot or old resin mass (original). : 
NATURAL ENEMIES. 
Two hymenopterous parasites were bred from the syrphid puparia. 
Dr. Wm. H. Ashmead, of the U. S. National Museum, ‘identified one 
of these as an ichneumonid (Syrphoctonus maculifrons Cr.) and the 
other as a chalcidid (Hutelus flavipes Walk.). Both species are fairly 
common, and probably aid greatly in keeping the trouble in check. 
Syrphoctonus maculifrons Cr.—This is a small wasp-like ichneumon 
fly about 0.86 inch in length. It has a dark body marked by a 
few white patches at the bases of the wings and legs. The face is 
nearly covered by a square of white, and the legs are reddish brown. 
The abdomen of the male is more slender than that of the female, and 
the white square on the face is larger. The earlier stages are not known. 
Pupation takes place in the body of the maggot in the outer resin mass. 
The adult emerges during the latter part of June or the first of July. 
