THE BRITISH NATURALIST. 



129 



The Occasional Phenomenal abundance of certain forms of 

 insect life, by W. E. Sharp. — This reprint from the Transactions of 

 the Liverpool Biological Society, deals principally with the occasional 

 abundance of DeilepJiila gain. Our esteemed contributor attempts to 

 connect the occasional abundance of this species, with dry weather 

 and low average temperature. We think the immigration theory is 

 now very generally accepted, and that it will be difficult to displace it 

 with another, but Mr. Sharp argues, as he always does, with consider- 

 able force, and marshalls his facts in a very striking manner. The 

 pamphlet is an interesting addition to the controversy which 

 appeared in our own pages, and though he has not convinced us, we 

 must say he makes out a very good case. 



Recreation, by William Odell, F.R.C.S. Eng. — A valuable 

 argument in favour of athletics for those who have much brain work 

 in early life. The author shows that while the leaders of the scientific 

 world are men of splendid physique, those who have been noted at 

 school or college for their athletic performances often rise to great 

 eminence. As an illustration he tells us that " in the very first boat 

 race between the Universities, three men who afterwards became 

 bishops rowed in one of the boat, and another rowed in the other." 

 Whilst we agree with all the author says, and cordially recommend 

 the book to those interested in the training of youth, we are of opinion 

 that Natural History offers a fine field for those who have no taste for 

 Athletics, and we do not think those who have given attention to such 

 pursuits, have suffered at all in competition with their fellows. 



THE GENUS SILPHA, Linne.* 



BY REV. W. F. JOHNSON, M.A., F.E.S., AND G. A. LEWCOCK. 



The members of this genus form one of the great sub-divisions of 

 the tribe Silphina and belong to the sub-order Clavicornia. They 

 differ from the genus Necrophonis in having eleven joints in their 

 antennae, whereas the former possess but ten. This difference, 

 however, is more apparent than real, as a close examination of the 

 Necrophorus antennae reveals an almost imperceptible second joint — it 

 is perhaps more distinct in specimens of N. humatov and N. vespillo 

 than in other members of the genus, although it varies considerably in 

 these species. Apart from this distinction, however, the antennae 

 gradually thicken towards the apex, but in Necrophonis they terminate 

 with a strong four-jointed club. Then, again, in Silpha the head is 



* Read at Meeting of City of London Entomological and Natural History Society, 



May 16, 1893. 



