The Scottish Naturalist. 39 



of it in this country is, that it is quite limited to the Scotch 

 fir. 



I. ferrugineus, Fab. — Found under the bark of the Scotch fir. 

 This species likewise frequents the Finns maritimus, where 

 it lives at the expense of species of the genus Hylastes ; its 

 metamorphoses have been described by Perris. 



Rhizophagus depressus, Fab. — This common species also in- 

 habits the Pinus maritimus, as well as the Scotch fir, and its 

 larva, which lives at the expense of Hylesinus, has been de- 

 scribed, as well as its transformations, by Perris. The 

 generic name was given under a mistaken idea of its habits. 



R. ferrugineus, Payk. — Also a common attache of the fir ; its 

 larva has not been described, but it is undoubtedly carni- 

 vorous. 



Dendrophagus crenatus, Payk. — Of this species hitherto only 

 a few specimens have occurred in Britain ; they have been 

 found at Rannoch under fir bark. I believe the larva and 

 its habits are unknown. 



Elater tristis, Linn. — Has been found very rarely at Ran- 

 noch. In Sweden it is associated with the fir ; its larva 

 has not been described. 



Athous undulatus, De Geer. — I am not sure whether this 

 fine, (and in this country very rare,) species is attached to 

 the fir or the birch ; it has been found only at Rannoch. 

 Out of the United Kingdom it has a very wide distribution, 

 occurring in the Altai, Siberia, and Hudson's Bay ; De Geer 

 described the larva, as well as the perfect insect. 



Eros aurora, Fab. — This elegant insect has been found in 

 Britain only at Rannoch, where it lives under the bark of 

 the Scotch fir, and especially among the decaying chips, the 

 the accumulation of years, at the saw-pit at Dall, there. 

 The larva has not been described, but I have reared the 

 perfect insect from a larva I took to London with me ; it fed 

 readily on lepidopterous larvae. 



Thanasimus formicarius, Linn. — This insect is found in 

 various parts, but, I believe, in Britain only in connection 

 with the fir. Its larva is well known, and has been several 

 times described ; it is supposed to be very useful by attack- 

 ing and destroying insects injurious to the tree. 



