82 RHYNCHOPHORA. 
by the distribution of the Conifer, which do not extend further south than 
Nicaragua. . 
The richest subgroups are the Platypi and Corthyli, represented each by some fifty 
species. The latter includes many of the most remarkable and highly-specialized forms 
found in the region. 
My especial thanks are due to M. Severin, of the Brussels Museum, and Herr 
Ganglbauer, of the Vienna Museum, who have freely placed at my services the 
types of Chapuis and Ferrari, respectively under their care. I also have to thank 
Dr. Horn, Mr. A. D. Hopkins, and Mr. H. F. Wickham for numerous examples of 
N.-American species. 
Unfortunately, many species described from the United States by Leconte and others 
are still unknown to me, and the published descriptions are too terse and based too 
exclusively on points of difference between congeners to afford any safe guide to the 
identification of Neotropical forms. Brief descriptions of Scolytide are not of the 
slightest use, except when dealing with a limited and tolerably familiar fauna, and 
those of Eichhoff, which can be safely followed even without types, are models of full 
and accurate definition. 
The fact that in some genera I have had before me types of almost all the known 
species has induced me to extend my account of them by giving descriptions of a few 
forms not yet found within our limits, or by including all described species in the 
analytical Tables. The genera selected for extended treatment are Neotropical, and 
such as can be treated in tolerably complete detail with the assistance of previous 
descriptions. Examples will be found in Phiwodorus, Cnesinus, Hylocurus, &c., the 
names of species not recorded within our region being given in square brackets. 
Secondary Sexual Characters. 
In Scolytide almost every part of the external skeleton may be structurally modified 
to present secondary sexual characters, correlated, not merely with the functions of 
recognition and coition, as is so often the case, but with the parts played by one or the 
other sex in burrowing and oviposition. To the latter functions is probably due the 
greater development of the scape in the females of Tesserocerus and Crossotarsus, and 
of the club in those of Corthylus; and the unsuspected existence of such female 
characters has caused much confusion in the description of species, of which the sex 
had not. been made out by dissection. 
The genitalia have been examined in many European species by Lindemann 
(Bull. Soc. Mose. xlix. 1, pp. 196-252), but without discussion of the secondary sexual 
characters. 
Recently Mr. Hopkins has published an account (Canad. Ent. xxvi. pp. 274-280) of 
