180 THE CANADIAN RNTOMOLOGLST. 



Antenna? short, filiform, 5- or 6-jointed, the third joint shorter than 

 the fourth ; basal joint of hind tarsi longer than their tibije,much 

 flattened and produced outwardly at apex beyond the second 



joint Teredofi, Norton. 



2. Antennae short and equally thickened or somewhat thicker before apex, 

 the third joint usually a little shorter than the fourth, or at least no 



longer ; hind tarsi dilated in ^ Tremex, Jurine. 



Xeris, Costa. 

 To this genus belong Urocerus caudatus, Cr., and U. Morrisoni, Cr. 

 Family III. — Xiphydriid^. 



Most European and American writers have placed these insects with 

 the Siricidse, but their habitus is quite different, and the characters used 

 in my table readily distinguish tlieni from the true horntails. 



The Swedish entomologist, C. G. Thomson, in 1871, first separated 

 them from the Siricidce as a distinct tribe, and in this he has been followed 

 by Cameron and Konow. 



I have recognized two subfamilies separated as follows : 



Table of Subfamilies. 



Front wings with one submarginal cell Subfamily I., Derecyrtinse. 



Front wings with two submarginal cells Subfamily II., Xiphydriinse. 



Subfamily I.— D£RECYrtin.e. 



This group is represented by a single genus, known at present to 

 occur only in Central and South America. 



Front wings with four submarginal cells Derecyrta, Smith. 



Subfamily II. — Xiphydriin^. 

 Three distinct genera are now recognized in this group, all being 

 found in our fauna. They may be separated as follows : 



Table of Genera. 



Front wings with three submarginal cells 2. 



Front wings with four submarginal cells. 



Lanceolate cell contracted beyond the base and 



closed Brachyxiphus^ Philippi. 



Lanceolate cell subcontracted, but still open. . .Xiphydria, Latreille. 

 2. Lanceolate cell contracted and uniting beyond the 



base Konowia, Brauns. 



