AMERICAN COLEOPTERA. 115 



In the Proc. Zool. Soc. London, Nov. 1872, Dr. LeConte gave in 

 greater detail than had been done a description of its anatomy, especially 

 of the mouth parts and expressed the opinion that Platypsylla was 

 a Coleopteron not very remote in its affinities from Leptinus. With this 

 opinion I fully agree. 



I have before me the dissection of the mouth parts made by Mr. Mat- 

 thews and another prepared by myself which are illustrated by the an- 

 nexed plate. As these differ somewhat from those given by Dr. LeConte 

 and subsequently by Westwood, (Thesaurus Oxoniensis, 1874), attention 

 will be called to the differences. 



The antennae consist of a long basal joint followed by a broader 

 cupuliform piece which seems to be composed of two joints. Within 

 the cupule is an oval mass composed of six segments. Westwood and 

 LeConte give a greater number of segments to the mass but do not 

 mention the division of the cupule. 



The mentum being easily seen without dissection, my figure does not 

 differ essentially from that of those authors. 



The maxillre are composed of two lobes, both thin and translucent, the 

 inner especially so. The outer is ciliate with long hairs on its outer side 

 from the insertion of the palpus to its apex. The inner lobe is long, 

 wedge-shaped, truncate at apex and ciliate with very short hairs. The 

 palpus is four-jointed as shown in the figure. 



When the mentum and maxillae are removed and the head viewed 

 from the under side the following structures become evident. 



The frontal suture nearly straight defines the clypeus, which has at its 

 middle a small oval dark spot being a point at which the chitin is denser. 

 Immediately posterior to this spot is a small somewhat pentagonal piece 

 articulated at its base a little in front of the frontal suture and which is 

 the labrum. Posterior to the labrum on each side is a small oval spot. 



Immediately behind the labrum the edge of the mandible can be 

 detected. This organ is extremely thin and transparent and is with 

 great difficulty defined. The illustration is as far as I have been able 

 to follow its outline. That this is not merely a line of sculpture on 

 the head has been rendered evident to me by the removal of the struc- 

 ture from the opposite side of the head, but I have not been able to 

 isolate the mandible 



Prof. Westwood was unable to find any trace of the mandible. After 

 a very careful study of the piece which has been figured by Dr. LeConte 

 as the mandible I am convinced that it is really one of the granules 

 which occur behind the labrum, and that the apparently serrate edge 



