YIII. 



NOTE ON THE PUPATION OF THE STAG-BEETLE. 



By Aethue Cottam, F.R.A.S. 



Bead at Watfurd, 20th January, 1880. 



The stag-bcctk' {Lucanus Cenms) is occasionally found in Hert- 

 fordsliire (as mentioned in my paper on our British beetles read 

 before the Society recently), but it can hardly be looked upon as 

 an insect that a collector in Hertfordshire only would be sure to 

 come across. In its usual habitats it is, however, an exceedingly 

 common insect, and in Kent, Surrey, Essex, and Suifolk one would 

 be almost certain to find it, probably iu some numbers. 



The larva feeds on wood, generally in old oak trees, and like 

 most wood-feeders, it usvuilly changes into a pupa iu one of its 

 burrows, and there changes into the beetle. From a note in the 

 English edition of the 'Insect World,' by Louis Figuier, it appears 

 that it is known to bury itself in the ground, and there change 

 into a pupa. Many of the larvae of the Noctufe amongst the 

 Lepidoptera bury themselves and change into pupas underground, 

 but I am not aware that any wood-feeding larva of a moth changes 

 to a pupa in the earth. It is remarkable that a wood-feeding larva 

 of any kind should have the power of forming a " cocoon " of earth, 

 for it must be necessary that it should have the power of exuding 

 some fluid of which to make a paste of the earth. In its natural 

 condition, changing into a pupa in the wood, no such power would 

 be necessary. Accompanying this paper is a portion of a 2:)upa-case 

 formed of earth by the larva of the stag-beetle. It is very hard, 

 and beautifully smoothed internally. 



About a fortnight ago two professional collectors of Lepidoptera 

 were at work in Epping Forest digging for pupas, and in a bank 

 they came upon an enormous pupa-case, in which, when they had 

 broken it, they found a perfect stag-beetle. Further digging pro- 

 duced three others : two of the four contained male, and two female 

 stag-beetles, all in the perfect state, though torpid. I possess one 

 of these pupa-cases, in which a hole has been made sufficiently 

 large to show that within is a perfect male stag-beetle. It would 

 therefore appear tliat the pupa changes into the perfect insect early 

 in the Avinter, and that the beetle remains dormant in the pupa-case 

 until its usual time of appearance. 



A large number of beetles hybernate in, or near the surface of, 

 the ground, and may sometimes be found during the winter in 

 considerable numbers together in a torpid state, but it is a new 

 fact, so far as I know, that an insect should come to maturity and 

 then remain in the pupa-case for some months before emerging. 



These beetles, which have now (at the beginning of January) 

 been found in a perfect state in their pupa-cases, would probably 

 not have been found on the wing till about the end of May or 



