30 GEO. H. HORN, M. D. 



to ten serrate, sometimes pectinate in the male ; epistoma variable, usually very 

 narrow at base; propectus with an entire juxta-siitural sulcus limited externally 

 by an entire carina (except in liumeralis) ; lateral supplementary carina distinct, 

 variable between the species : posterior coxal plates variable, usually narrower 

 externally, in two species parallel ; tarsi slender, the first joint of the posterior 

 pair usually as long as the next three, the fourth joint usually broader and lobed 

 beneath (except in two) ; claws variably dilated at base. 



Before presenting the table of species and entering upon their de- 

 scription it is well to explain the meaning of several terms originated 

 by Bonvouloir, and which I have retained for the sake of uniformity. 



The anterior supplementary carina is an elevated line connected 

 with the apical marginal ridge near the front angles and directed 

 backward. This carina is short in all the species except pectinatus, 

 in which it extends to the middle of the side of the thorax. 



The posterior supplementary carina begins at the tip of the hind 

 angle beneath and extends forward more or less sinuously, it is rarely 

 long, in two species very short {audax and imperjecius) and in another 

 (pectinatus) entirely wanting. This carina is really the true lateral 

 margin of the thorax, as in some Cardiophorini. 



The j K.rta-sutural sulcus, to receive the antennae when at rest, follows 

 nearly the line of the prosternal suture, it is limited externally by a 

 well defined ridge, which is entire exce])t in humeralls and imperfectvs. 



The other terms are such as are commonly used, and need no ex- 

 planation. 



There seems to be a tendency in our species to show the gradual 

 obliteration of the characters which separate Adelothyreus and Mi- 

 crorhagus by the disappearance of the posterior portion of the outer 

 carina of the sulcus, the wide coxal plates and the simple tarsi. 



In his tabular arrangement of the species Bonvouloir prefers to 

 start with characters drawn from the supplementary carinas. The 

 form of the coxal plates seems to me of far greater importance (it 

 has more than generic value in some parts of the series) in enabling 

 us to show more clearly the relationship between Microrhagus and 

 Adelothyreus. 



In a paper entitled " Throscides et Eucnemides Gallo-Rhenane," 

 by A. Fauvel (Rev. d'Entomologie iv, j). 338) the name Dirrhagus 

 Latr. is adopted in lieu of Microrhagus. 



The following table will enable the species to be readily distin- 

 guished : 



Posterior coxal plates dilated internally, narrow externally 2. 



Posterior coxal plates parallel, not dilated internally ; posterior supplementary 

 carina very nearly entire 8. 



