42 LUCANID^. 



cJ. Head large, with its outer margins nearly always more or 

 less crown _'d with strong ridges. Legs, antennse and palpi 

 very long and slender. Mandibles long, generall}^ very greatly 

 developed. Epistome verticallj- produced and narrow, often 

 with a clypeal jsrocess, sometimes forked, above. 



The variable number of joints forming the club of the 

 antenna is a remarkable feature of the genus. This is 

 probabh^ not a primitive survival, but a late development by 

 which an increase of sensory surface has been acquired. 

 Sexual dimorphism occurs in almost every degree of develop- 

 ment in the different species, from the extreme found in the 

 largest specimens of L. laminifer and canton to its almost 

 total absence in L. gracilis, of which the male originally 

 described was supposed to be a female. The j)rimitive 

 Priodont form of the mandible, with straight, serrate inner 

 edge, does not occur in Lucanus and dimorphism of the male, 

 as found in Calcodes, etc., is unkno^\^l. 



The clypeal fork found in L. lunifer and other species is a 

 very peculiar feature but it is absent in most of the species 

 and, no doubt, in very small specimens of all. It is 

 noteworthy that, although the length of this structure 

 increases with increased size of the specimen, the bifurcation 

 diminishes. 



Key to the Species of Lucanus (males). 



1 (26) Front tibia not finely serrate externally. 



2 (.3) Head with a median and two lateral 



proce.sses rising abruptly laminifer Wat., p. 44. 



3 (2) Head without abruptly ri.sing pro- 



cesses. 

 ■4 (9) Clypeal process forked. 



5 (6) Middle and hind femora blotched with 



red lunifer Hope, p. 45. 



6 (.5) Middle and hind feniora entirely dark. 



7 (8) Upper surface closely hairy furcifer, sp. n., p. 46. 



8 (7) Upper surface not closely hairy f>'yi' Boil., p. 48. 



9 (4) ("lypeal process not forked. 



10 (21) 3Iiddle and hind femora and tibise with 



red or yellow stripes or blotches. 



11 (18) Elytra more or less hairy. 



12 (17) Elytra not or scarcely metallic. 



1.3 (16) Posterior lobes of the head broadly 



rounded. 

 14 (l.j) Tronotum and elytra very finely and 



densely punctured smithi Parry, p. 49. 



).5 (14) Pronotum and elytra loss finely and 



densely punctured villosus Hope, p. .50. 



16 (18) Posterior lobes of the head narrowly 



rounded ". cnntori Hope. p. .51. 



17 (12) Elytra inetallic green or coppery inraresi Hope, p. .52. 



18 (11) Elytra not hairy. " [P- 54. 



19 (20) Prothorax narrow fairmairei Planet, 



