COLEOPTERA. t 



result of considerable inconvenience, experienced in consulting several works 

 where the description of one species refers to that of another, and this in turn 

 often to a third, thus necessitating a large amount of reading and reference 

 before the full description is reached. Although, by the method proposed, 

 there must be a large amount of repetition, it is hoped that the convenii 

 in having all the parts of a description under its own heading, will repay 

 the additional labor. The descriptions have invariably been taken from 

 males, when present, unless the contrary is stated. 



In describing the sexual modifications, various terms are employed, which 

 it may be well to explain as follows : — 



Emarginate. — This term is applied to an abrupt discontinuity of an edge, 

 the line joining the two points of discontinuity being reentrant, and more or 

 less broadly rounded. A certain latitude is allowed in the greater or less 

 prominence of the exterior angles, they being in some cases slightly roundel, 

 in others very prominent, acute, and projecting, and also in the degree of 

 curvature of the line forming the reentrant ; this, though in the great 

 majority of cases very broadly rounded, may in certain instances be rather 

 acutely so, which is particularly the condition, when the emargination 

 approaches in configuration the more or less triangular notch known as an 

 incisure. 



Sinuate. — When the line bounding the vertex of a segment is uninterrupt- 

 edly curved throughout, but reentrant in the middle, it will be designated 

 by this term. In this case the reentrant portion is called the sinus, and the 

 two lateral rounded projections the apices. Comparisons are frequently 

 drawn between the degrees of curvature of the sinus and apices, as will be 

 seen subsequently, and will be understood to refer to the points where the 

 curvature is a maximum, or at the bottom of the sinus and tips of the apices. 

 If a right line be imagined drawn tangent to the apices, the distance from 

 it to the bottom of the sinus will represent the depth of the latter, and the 

 distance between the points of tangency its width ; the same rule is appli- 

 cable to the measurement of all notches and emarginations. 



Incised. — When the emargination takes the form of a triangular notch, this 

 term will be applicable. The anterior angle is called the angle at the vertex, 

 anterior angle, or simply the angle of the incisure ; the points at which the 

 posterior edge of the segment becomes interrupted to form the notch are 

 designated the exterior angles. The sides of the notch are generally straight, 

 and should always lie so understood, unless the contrary is expressly stated, 

 and a slight latitude is allowed, in that all the angles may be slightly 

 rounded, and the sides sometimes arcuate or sinuate ; the former is very rare, 

 but occurs in the genus Areus. 



Bilobed. — This term I have applied when the tip of a segment is emarginate, 

 the notch being a perfect cusp in outline, and the sides or arms being widely 

 divergent and evenly curvate. We have in this case the two uninterrupt- 

 edly rounded apices, as in the instances cited under the term sinuate ; but 

 here the edge is acutely notched in the middle. The only latitude allowed 

 in this instance is that the cusp may in certain forms be narrowly rounded ; 

 these cases are distinctly stated, otherwise the term is to be considered as 

 indicating a perfect cusp point. 



