66 SEX 



males have often more elaborate antennae 

 and other sense-organs, which are important 

 in finding the female. Among the Dynastid 

 beetles the males often have extraordinary 

 horn-like projections from the head and 



Fia. 13. The Hercules Beetle Dynastes. In the male (M) 

 a horn on the back of the head works against a still larger 

 horn arising from the top of the prothorax. The female 

 (F) is smaller and without the horns. 



prothorax (see Fig. 13). They are out- 

 growths of the chitinous cuticle and cannot 

 be moved of themselves, though they may 

 be brought together like the limbs of tongs 

 when the head and the prothorax are moved. 

 Their use is uncertain. In the stag-beetles 



