BEETLES. 63 



i'AMiLY XXII. LUCANID^ (Stag Beetles). 



Mandibles sometimes large and projecting like antlers. 

 Antennae elbowed, and fitting into excavations on the sides of 

 the head. The basal joint is long, and there are several pec- 

 tinated or serrated immovable joints at the end. The abdomen 

 has five segments. These imposing beetles liy about chiefly 

 at night, and feed upon the exuding sap of trees. The larvse, 

 which are maggot-like, live on old decaying trees, and often 

 require from two to three years for their transformations. 



Genus Lucanus, Linn. 



Pronotum separated from the elytra by a small interval. 

 The sixth abdominal segment is not visible. The antennae 

 have four expanded terminal joints, pectinated on the inner 

 side. The labrum is narrow and curved down between the 

 maxillae. The latter are large, and in the males much longer 

 than the head, but shorter in the females. The border of the 

 head is produced half across the eyes. 



* L. cervus, Linn., the Stag Beetle (Plate VII., Fig. 1, male ; 

 Pig. 2, female). This well-known beetle is very variable in 

 size, and some specimens are only half as large as others, 

 probably owing to the larvae having obtained inferior or 

 insufficient nourishment. The larvse live in old rotten oak 

 trees, and are most common in the southern counties. The 

 larva takes five years to complete its metamorphosis. 



Genus Platycerus, Geoff. 



The sixth abdominal segment is visible, and the eyes are not 

 excavated. The only species is : 



P. carahoides, Linn. (Plate VIL, Fig. 3). This varies much 

 in colour, and may be green, violet, blue, or black, darker 



