Chapter VII. 



INSECTS INJURIOUS TO THE BIRCH. 



Betula nigra, B. populifoUa 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 many 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 insects, 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 slexder xiphidria. 



Xiphidria attenuatus Norton. 



Order Hymenoptera ; family Urocerid^. 



This " horn-tail " borer is rarely me^t 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- 



*A8 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 tbem in foot-notes. 



483 



