AMERICAN IIYMENOPTERA. 31 



Catalogue of the described TENTHREDINID^ and TJROCERID^ of North 



America. 



BY EDWARD NORTON. 



[Communicated March 11th, 1867.] 



This paper is not presented as a complete monograph of these Fa- 

 milies, but simply as a catalogue of the genera and species of this con- 

 tinent, with references to all the described genera known to the com- 

 piler, for the information of American students who have not access 

 to the original descriptions. 



It is to be hoped that it will lead to a closer and wider study of these 

 the most injurious of all Hymeuoptera to our trees and plants. As all 

 of their larv;>3 live on leaves or woody fiber they may all be classed as 

 injurious to vegetation. 



In some genera it is very difficult to define a true species, because of 

 the variation in color. This is particularly the case in Nematus and 

 in Teiitlirrdo. And doubtless some of the species described here, will 

 prove to be varieties. Mr. Walsh has shown that in some species of 

 Eaara and Nematus bred by him, it was almost impossible to detect 

 any diiference in the imago, while the larvae varied greatly. Doubtless 

 our present opinion will be greatly modified by future discoveries. The 

 bullae which appear in the wing nervures of all these insects, and 

 which are much noticed by Mr. Walsh, are only referred to in this 

 work, because they have not been sufficiently studied by the writer. 

 Although not caused by the folding and unfolding of the wings, they 

 seem to indicate the points at which the wings are folded or unfolded, 

 and the hinges at which they can be bent without breaking. As the 

 same arrangement is often common to several genera, it seems probable 

 they may prove of value in defining Tribes or groups of genera; a most 

 desirable point, as will be seen in the deficiency of many of the gene- 

 ric distinctions hereafter presented. 



It is fitting to acknowledge with thanks, the receipt of insects for 

 examination from many persons, especially the following : A. S. Pack- 

 ard, Jr., from Maine and Labrador; S. H. Scudder and A. F. Sanborn, 

 from 31assachusetts ; J. Akhurst, W. H. Edwards and Mr. Calverley, 

 New York and Virginia; P. H. Uhler and T. Glover, from jMaryland ; 

 Baron Osten Sacken, District of Columbia and elsewhere. Thanks are 

 also due to Prof. Agassiz for affording free access to collections in the 

 Cambridge Museum; S. H. Scudder to the collection of Dr. Harris, in 

 the Bost. Soc. Nat. Hist. ; E. T. Cresson, to the collection of the 



