Chapter VII. 
INSECTS INJURIOUS TO THE BIRCH. 
Betula nigra, B. populifolia and B. alba. 
A considerable degree of interest attaches to the birch insects, not 
only because the birch is a beautiful shade tree, but because many of 
the species injurious to the different species of Betula also occur on 
other shade trees, as the oak, while mauy of them have established 
themselves in orchards and gardens. In our Bulletin on Forest Insects 
we enumerated only 19 species of birch insects ; these we increased to 
50 ; afterwards Mrs. Dimmock, in her invaluable article on the insects 
of Betula in North America, published in Psyche, enumerated 107 
determined species, besides several undetermined.* Mrs. Dimmock has 
kindly allowed me to reproduce the article, which I have done, under 
the head of the different species. I have also added a number, mostly 
undetermined larvae, so that now the chapter contains references to or 
descriptions of 105 species. Kaltenbach enumerates 270 European 
birch-feeding iusects, and judging from the number occurring on other 
kinds of trees the number in this country will probably ultimately be 
found not to be less than that of the birch insects of the Old World. 
INJURING THE TRUNK. 
1. The slender xiphidria. 
Xiphidria attenuatus Norton. 
Order Hymenoptera ; family Urocerid^e. 
This "horn -tail" borer is rarely met with. The generic name was 
given to it from the appearance of the sword-like ovipositor, which, 
however, is much shorter than in Tremex, a member of the same fam- 
ily. The body of the imago or fly is a little flattened, somewhat turned 
up behind, and the tip of the abdomen ends in an obtuse point, while 
the antennae are short, curved, and tapering at the end. 
The present species was taken by Mr. W. H. Patton, on June 6, at 
Waterbury, Conn., from a dead stick of the black birch. "My atten- 
*As some of the species enumerated in her list feed only on decaying wood and 
under the bark I have not numbered them as true birch-feeding insects, but referred 
to them in foot-notes. 
483 
