INTRODFCTION. 13 



France is said to have occurred some years previous to 

 1863, when, during a period of extreme drought, a cloud of 

 the insects sufficient to obscure the sun passed southwards 

 to a less arid region in tlie Department of the P\Tenees 

 Orientales. The latter account, recorded by Planet in his 

 ' Essai Monographique sur les genres Pseudohicane et Lucane ' 

 (p. 41), seems scarcely credible. Perhaps the finding of a 

 few specimens of the Stag-beetle at the time of the passing of 

 this surprising swarm led to a too hasty conchision as to the 

 insects composing it. 



The active adult life of the Lucanid^ seems to be short. 

 L. cervus ap})ears at the end of May or the beginning of June, 

 and is only occasionally seen after the middle of July. In 

 the Himalayas various species are abundant during the montlis 

 of July and August. Various accounts have been given of 

 the contests that occur between the males of the British 

 Liicanus cervus, which seem to considerably outnumber the 

 females. Kirby and Spence describe them as attacking each 

 other with great fury, but the encounters seem to be generally 

 of a harmless nature, rather clumsy scuffles for possession of 

 the female. It is very doubtful whether the mandibles can 

 be correctly described as weapons in these struggles. The 

 beetles appear to be actually without the means of inflicting 

 injuries, such as often occur in similar contests between male 

 insects not provided with enlarged mandibles. Certain 

 species with shorter and stouter jaws are perhaps capable 

 of inflicting more serious injuries but, although males are 

 sometimes found bearing scratches, probably resulting from 

 these contests, they are generally very superficial. 



DiMOBPHISM AND POLYMORPHISM. 



Although the two sexes never differ so completely as in 

 those insects the females of which are wingless and larva-like, 

 sexual dimorphism seems to attain in the Lucanid^e almost 

 the extreme of possible difference for beetles in which both 

 sexes are fuUy developed. Male and female of the same 

 species may be dissimilar in practically every resi)ect, so that 

 their correct association becomes a most perplexing problem. 

 There are a few genera, e. g., Figidus, the species of which are 

 of small size, in which the two sexes are alike externally l)ut 

 this is quite unusual. In other genera dwarfed males may 

 rather closely resemble the females and such specinu^ns often 

 afford the best means of associating the sexes, but the larger 

 the size of a male specimen the less it resembles the female, 

 until in fully developed exani])les the dissimilarity may be 

 comi)letc, so that, in many cases, it is difficult to find any 

 single feature alike in both. 



