ZOOLOGY. 113 



During the progress of the investigations which wil terminate in 

 the classification, according to the scheme there proposed, of 

 the genera and species by which the Rhynchophora are repre- 

 sented in our fauna, I have been led to observe an additional char- 

 acter serving to define this great and important complex of genera. 

 This character strengthens greatly the opinion I first announced 

 concerning its systematic value, as an equal of all the other Cole- 

 optera combined. 



On separating the head of a Rhynchophore, it is seen that the 

 cranium (I use this word for want of a better term) is globose, 

 and always presents a distinct trace of a median suture on the 

 under surface corresponding with the gular sutures of other Cole- 

 optera. In the latter, however, these sutures diverge either be- 

 fore or behind, and rarely (SilphidtB and Staphylinidae), approxi- 

 mate at the middle of their course. Whether the difFei^ences in 

 direction of these sutures may or may not, when carefully studied, 

 give indications for the definition of the series into which the nor- 

 mal Coleoptera are now divided upon other characters, I cannot 

 now say. But this much I can assert positively, that in no other 

 but the Rh^^nchophora, do the lateral elements of the under sur- 

 face of the head coalesce on the median line, so as to form a 

 straight longitudinal suture extending to the posterior limit of the 

 chitinous part of the head. 



In most of the Coleoptera thfe gular sutures diverge behind, and 

 even when they are obsolete, their posterior termination is indi- 

 cated by a nick or irregularity in the outline of the infero-poste- 

 rior margin of the cranium. In the Ptinidse and Bostrichidte, by 

 a remarkable exception, the sutures, though distant in front, con- 

 verge behind. 



It will not be in my power, for some time to come, to follow 

 this train of investigation to its limits, and I now make known 

 these imperfect observations in the hope of inducing observers, 

 who are less burdened with a great mass of material urgently 

 pressing for classification, to give some attention to the valuable 

 characters here indicated. — J. L. LeConte, M.D. 



[Printed at the Salem Pkess, February, 1875.] 



