4 BULLETIN 108, UNITED STATES NATIONAL MUSEUM. 



since they agree more or less closely with the adult in their mouth 

 parts. It is probable that there is some difference between workers 

 of allied species/ but I have not observed them, and in Rcticulitermes 

 there is little difference between soldiers of allied species, and, in- 

 deed there is no need, as far as the separation of the species is con- 

 cerned, that either soldier or worlrer should possess peculiar char- 

 acters, but the existence of such peculiar structures in either soldier 

 or worker is an argument for the distmction of the s] ecies, since 

 these peculiarities are transmitted from generation to generation 

 by the adult insects. However, there is some dimorpliism in the 

 soldiere; in certain Kalotermes there are soldiers with short and 

 others with long heads, and in certain Reticulitermes the head of the 

 soldier varies in length. There is also variation in the size of soldiers, 

 particularly in Termopsis and Kalotermes, while in Constrictotermes 

 the soldier is m^ore constant in size. The nature of the pilosity is 

 constant and of great systematic value. There are no external 

 sexual characters that can be utiUzed to distinguish species, and 

 such are not necessary, for it is rarely that in any one locality two 

 species of a genus s\varm at the same time. Although the color is not 

 striking, it is very constant in each sj^ecies; likewise the size of the 

 adult is also fairlj- constant, and both are useful in classification. 



HISTORICAL SUMMARY. 



The fu'st of our termites to be described was T. marginipennis by 

 LatreiUe in 1832. In 1837 KoUar described T. ftavipes from a 

 greenhouse in Em'ope. In 1839 Burmeister described T. castaneus, 

 and in 1853 Walker described several and Haldeman two. In 1855 

 to 1857 Hagen ] published his famous monograph of the termites. 

 Since then Buckley, Desneux, and the senior author have added a 

 few species. In the Catalogue of om* Nem'0]>teroid Insects, 1007, 

 there are 12 species listed from the I'nited States; now we are able 

 to record 36 species and one variety. 



Of the 12 termite s})ecies listed as known in 1907, one species is 

 not included — " Eutermes" nigriceps Haldeman described from 

 Mexico has been discarded as lost or indeterminable. One new 

 s])ecies was added by the senior author in 1907 — Reticulitermes 

 (Termes) virginicus. Two of Hagen's varieties have been reestab- 

 lished from obscurity — Termopsis nevadensis and Kalotermes minor. 

 Three known species have been added to the fauna of the United 

 States, namely, Kalotermes (Termopsis) occiclentis Walker, Pro- 

 rhinotermes {Arrhinotermes) simplex Hsigen and Aiioplotermes (Termes) 

 fumosus Hagen. 



There are nov,- known 19 described ^iiecies and 17 species and a 

 variet}^ new to science. 



1 See Snyder, 1919. 



