AMERICAN COLEOPTERA. 29 



Synopsis of the FABNID^ of the United States. 

 BY GEO. H. HORN, M. D. 



It is now nearly eighteen years since the publication of the synopsis 

 of this family by Dr. Lecoute {Proc. Acad., Feb. 1852). In the 

 meantime a number of species have been added to the list, while many 

 others from California and adjacent regions, collected by myself, re- 

 main without names. The object of the present paper is to bring be- 

 fore the American student a complete list of our species with suffi- 

 ciently detailed descriptions to enable them to be readily determined. 

 Several errors in family characters, copied from one author to another, 

 have been detected and will be mentioned in their proper places. 



Among the species described from California, etc., will be found 

 several genera not before known from the western slope, enough to 

 warrant the belief that those regions are, at least, as well supplied as 

 the Atlantic slope. The dearth of species from our Southern States 

 is remarkable and is the result, probably, of a want of thorough explo- 

 ration rather than a real absence. 



Fully coinciding in the views of Dr. Leconte,the following sub-fami- 

 lies are adopted : 



Abdomen with more than five segments Psephenidae. 



Abdomen with five segments only; 



Anterior coxse transverse; trochantin distinct Parnidae. 



Anterior coxae rounded; trochantin invisible Elmidae. 



Sub-Family PsEPHENIDiE. 



The characters of this sub-family have been so fully given by Dr. 

 Leconte (loc. cit. and Clasa Col. N. A. p. 115) that it is not necessary 

 to enter into details here. Two errors, however, need correction. 



In examining the specimens in my cabinet I was unable for a long 

 time to detect the sixth segment spoken of by Dr. Leconte, which 

 shows itself on each side only, between the fifth and seventh segments; 

 those in the cabinet of Dr. Leconte exhibited the additional segments 

 very plainly. Dissection indicates that those with six segments only 

 arc females, while the males have an additional segment between the 

 last and the fifth. Accompanying this are certain antennal differences 

 not before noticed. The antennae of the male are distinctly stilj-semite 

 and the last joint at least one half longer than the preceding, those of 

 the female are almost monillform and the last joint not longer than the 

 preceding. The hind coxae are said to be contiguous (^Froc. Acad. 

 1852, p. 41, and Class Col. N. A. p. 115), this I find not to be the 

 case either in this sub-family or the next, at least, so far as our genera 

 are concerned. 



