394 Eev. H. S. Gorham's revision of the 



In the third we only see the result of high develop- 

 ment under favourable conditions for its taking place. 

 The few genera in this category speak of a settled and 

 prosperous home long enjoyed. They are the autocthones 

 of the country and occupy a precarious position, from 

 which any slight disturbance may speedily remove them. 



Or, in other words, the presence of genera of the first 

 category speaks of ancient settlement ; of the second of 

 permanent occupation ; of the third of duration under 

 favourable conditions. 



In my first category I do not include such abnormal 

 genera as combine the characters of two or three 

 families, and are not satisfactorily placed in either. 

 These I eliminate, as being only placed in either family 

 for the sake of convenience ; they are, according to my 

 view, the living representatives of a still older stock, 

 and are limited in distribution, and are rare just because 

 they represent a bygone and still more generalised type. 

 I speak here only of such genera as clearly belong to 

 existing families. Among the Lycidce there is a well- 

 known genus in Europe, Homalisus. It is what I would 

 call an undifferentiated family type, and one new genus 

 from Japan, Pristolycus, seems a parallel case. This 

 insect, with the general appearance of one of the Lycidce, 

 has the trochanters applied to side of the base of the 

 femora, as in the neighbouring families ; the antennae 

 are close at their insertion, as in Lycidce and Lampyridce ; 

 the middle coxae are very close, as in Telephoridce. 



Similar cases of rare abnormal genera, as we some- 

 times call them, will occur to every one. I repeat, that 

 while these are to me instances of my principle more 

 broadly applied, in treating of the family I refer here to 

 what are often called dominant genera, as, for instance, 

 Bembidium, with its outlying small genera, among the 

 Carabidce ; while Amphizoa, suggested to me by Mr. 

 H. W. Bates, is an instance of the generalised family 

 type. 



To illustrate my idea, the family with which I com- 

 mence this paper will serve my purpose as well as any 

 other, better than some, for some other families may be 

 deficient in the first or in the third categories, although 

 abundant in species, with but a moderate degree of 

 development in any particular direction. In the Lycidce, 

 one of the most remarkable developments is the inflation 

 of the elytra in the males. It is not my purpose here 



