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On Rearing Beetles of the Genus Qeotrupes. 



By Hugh Main, B.Sc, F.^.S.—Bead January llth, 1917. 



The life-history of one of these interesting beetles {Geotriijjes 

 stercorarii(s) was told us by M. Constant Sano and printed in our 

 " Proceedings " of last year. I was fortunate in getting a personal 

 introduction to the insect by our young friend, and I have since 

 made the acquaintance of several of the other species belonging to 

 the genus. 



M. Fabre, the illustrious French naturalist, recorded his observa- 

 tions of a number of the dung-beetles that occurred near his home 

 in Provence, and several of these are also found in Britain. The 

 specific names of some of these insects have unfortunately under- 

 gone a good deal of change, and it is by no means certain that the 

 beetle we now call G. stercorariitu is the species referred to by Fabre 

 or other earlier writers under this name. Hence apparent dis- 

 crepancies in the records of various authors about an insect may be 

 due to the fact that different species are being referred to under the 

 same name. As a case in point, Fabre gives the autumn as the 

 time of oviposition of G. stercorarius, while the insect which now 

 goes by this name lays its eggs in the spring, and it is our G. 

 spin'Kier, whose name he does not mention, which lays its eggs in 

 the autumn. The war has prevented me from getting direct 

 evidence on the subject from France, but I hope to obtain this 

 later on. 



It might also be put on record that the interesting account of the 

 parasitism of Aphodiiia porciis, related by Dr. Chapman in the 

 " E. M. M.," 1869, pp. 273-276, should be referred to G. s/dnvfer, 

 Marsh, as the host, and not G. sinrororiKs, L., the names having 

 certainly been transposed since the date of the published account. 



It has been difficult to learn exactly what happens in the case of 

 insects which carry on their work underground, but an " observa- 

 tion cage," which I have devised, allows one to watch in ease and 

 comfort the whole process of making " dug-outs " and furnishing 

 them with provisions for the nutrition of the young larv^, and the 

 later stages of pupation and emergence of the perfect insect. The 

 cage consists essentially of two sheets of glass separated by a dis- 

 tance corresponding to the width of the insects under consideration, 

 and the interspace is filled up with earth. Any one with a little 

 knowledge of carpentering can easily make a few cages and in spring 

 or autumn beetles can readily be found that will start work in them. 



