90 Proceedings of the 



fig. 2. M. Kraatz's description might lead us to suppose that 

 fig. 3 would best represent C. angustatus, F., but having had 

 under my eyes typical examples of all three, sent to me by 

 M. Kraatz, I find that none of them have the thorax widened- 

 more in front than fig. 2, which, indeed, fairly represents the 

 thorax of M. Kraatz's specimens of C. angustatus, F. But I 

 know that there are examples which have their thorax widened 

 as much in front as fig. 3. I possess one myself, and Sturm 

 gives that form in his figure of his C, angustatus. We must 

 therefore either make a fourth species to receive fig. 3, or else 

 admit that this subgroup is variable in the form of its thorax ; 

 and there need be no hesitation in adopting the latter course, as, 

 although I have not met with any specimen exactly filling up the 

 gap between fig. 2 and fig. 3, I have seen all grades of transition 

 between fig. 1 and fig. 2. Another point of difference, where we 

 constantly see a gradual passage between the one and the other, is 

 the colour of the thorax. In the typical C. castaneus, St., it is dark 

 pitchy black throughout, and the margins are not paler than the 

 centre, nor semitransparent. In both C. angustatus, F., and C. in- 

 termedins, Kr., the margins are paler, or semitransparent ; but I 

 have seen transition specimens where it is almost impossible to 

 say whether the margins are paler or not, in one view looking 

 paler, and in another quite dark and opake. Again, specimens 

 occur very slightly paler on the margins, and so on.. The punc- 

 tuation and depressions, and the spreading out and raising up 

 of the margins of the thorax also vary. I admit that I have 

 never seen the normal or perfect examples of C. castaneus, St., 

 with the spread-out and slightly bent-up edges of the C. angus- 

 tatus, F., or intermedius, Kr. ; but if, as I imagine, the latter are 

 less mature individuals, and castaneus, St., the more mature fully- 

 coloured and more solidified form, such a circumstance will suf- 

 ficiently account for the differences to which I have been alluding, 

 whether in punctuation, depression, or colour. Indeed, such a 

 supposition accounts for more ; for it is not only in the thorax 

 that these differences exist, but also in the whole of the rest of 

 the body. C. castaneus, St., is darker and more deeply punc- 

 tate on the elytra also, and the deeper colour extends to the 

 antennae, which are slightly darker at the point ; and this is only 

 what might be expected : we always find that where a greater 

 infusion of colour has penetrated through an individual, it is not 

 confined to one part, but pervades the whole system. I also 

 look upon the acuminate sutural apex of the elytra (referred to 

 by Kraatz as being possibly a sexual distinction of C. angus- 

 tatus, F.) as another indication of immaturity. I have never 

 seen this in C. castaneus, St., but I have found it indifferently 

 both in the males and females of C. angustatus, F. As to 



