6148 



Insects 



trees fas may be said are in a semi-decaying state from being cut down), now why 

 should we find these trees swarming with the Scolytus larvjE when there are hun- 

 dreds of fine healthy trees in the adjoining fields ? even two sides of the basin yard are 

 studded with elms, but you cannot find them attacked by the insect: why, I say, do 

 we not find them ? why, because it is not their proper or natural food : it is only in 

 those portions where disease has begun its work, and the insects are attracted to the 

 diseased portions, like most other lignivorous species to hasten on decay, which 

 appears to be their office, and that they carry out to the letter. — Edward Parjitt ; 

 4, Weirjield Place, St. Leonardos, Exeter. 



Scoli/tus supposed a secondary cause of injury : Cossus ligniperda does infest the 

 Elm. — In your paper read at the Entomological Society upon Scolytus destructor, the 

 inference you ])oint out is certainly the correct one, viz., that the trees were not suf- 

 fering from Scolytus so much as from Cossus. But my reason for writing to you is to 

 inform you of the fact that the larvfe of Cossus ligniperda does infest the elm, so much 

 so, that the greater number of valuable trees in Mount Edgecunibe Park are nearly 

 destroyed through the perforations of this larva: at least I suppose the larvae to be the 

 cause, but I cannot give positive j)roof, not knowing whether they were diseased pre- 

 viously, and not having tried to cure them. Cossus larv^se do not always mine to the 

 centre or interior of a tree, but are to be seen in the full-grown state lying in their 

 trenches on the surface of the wood, just under the bark. The last four larvse I took 

 were in the situation I describe. Passing by a tree I saw a patch of the bark loose, 

 and guessing the cause, I returned, took off the bark, and two great fat fellows were 

 exposed to view ; two more were another skin deeper. I have not met with Scolytus 

 destructor here ; I took one specimen at Exeter last year: our equivalent isHylesinus 

 crenatus. — /. J. Reading ; 11, Ham Street, Plymouth. 



[A number of letters have been received, the writers of which take the views indi- 

 cated by Mr. Parfitt and myself, that Scolytus destructor attacks only the in- 

 jured or dying trees, but I think Captain Cox is entitled to be heard in reply before 

 anything further is published on the opposite side of the question. In the present 

 state of the question I do not wish to enforce any opinion of my own. — Ed^ 



Beetles in Ants' Nests. — The attention of English Coleoplerists has of late been 

 more than usually directed to the search for the beetles usually found in ants' nests, 

 and the result has been that several species have been added to our native lists. This 

 year I have devoted some time to the subject, with a view not only of obtaining speci- 

 mens, but also of trying to discover what it was that induced the beetles to be 

 dwellers in habitations they had not assisted to build, and where, judging a priori 

 from the carnivorous habits of the proper inhabitants, they would be likely to lead very 

 uncomfortable lives. My observations have been exclusively confined to the nests of 

 the large wood-ant {Formica rufa), and, as far as I have been able to notice, the 

 beetles live in perfect harmony with the ants, neither attacking them nor being 

 molested by them. I have proved also by keeping the various species together in a 

 bottle for several days, that these beetles do not hurt each other. I should also 

 mention that the nests are full of Onisci of different sizes and colours, and possibly of 

 different species, but they and the ants do not quarrel in the least. The si<>ht of these 

 Onisci led me to think that they were there, as in other places, on account of the pre- 

 sence of moisture or decay which favour their existence, that they were not tenants at 

 ihe will of the ants, but lodged in their nests rather in spite of them. This hypothesis 

 did not seem very easy of dcmoubtration, but luckily I stumbled on that which threw 



