110 E. P. Stebbing — Discovery of Thanasimus sp. prox. nigricollis. [No. 3, 



activity in the spring until the autumn. That the insect has an 

 adequate food-supply will be evident from the following facts: — 



From calculations made from measurements and countings taken in 

 the forest I estimated that in a deodar tree of a hundred feet length 

 of bole and three feet diameter at base which had been felled at the end 

 of April and in which the scolytids had deposited their eggs in the bast 

 layer from top to base, a first generation of some 56,300 adults was 

 produced in July- August. Taking but 50 per cent, of tbe eggs (S. major 

 lays about 60 and S. minor 40 per brood) laid (these being those of the 

 second generation of the year) by these 56,300 beetles as arriving at matu- 

 rity, we have the enormous total of 1,550,000 beetles at the end of the year, 

 the result of the eggs laid in but one tree in the spring. I may say that 

 in this calculation large deductions have been made to allow for over- 

 estimation, &c, the large number of beetles which oviposited in the giant 

 crown of the tree and their resultant offspring being left out of account 

 altogether. Experiment has shown, however, that the Thanasimus is by 

 no means dependent upon the Scolytus beetles for its food-supply as it 

 will devour with almost, if not quite, equal avidity, various other 

 scolytid pests found in the region of its known activity. I have fed it 

 with the following beetles: — 



1. Bark-boring species (i.e., those species which confine their at- 

 tacks to the bast layer of the trees attacked). 



Scolytus major Steb. MS. ") ,. n . /1r , _ A 



^ . «1 i ikxci \ mentioned above ( Deodar). 



8. minor Steb. MS. ) v 



Polyqraphus major Steb. MS. ),,->, . iri 



-^ . c A , ■»,« t (Blue pine and bpruce). 



P. minor Steb. MS. ) r ' 



Pityoqenes coni ferae Steb. MS. < ' n ->• ' \ 

 ^ * J (_ Gerardiana). 



Pinus 



Tomicus sp. (Blue pine and Spruce). 

 2. Wood-boring species (i.e., those species which bore right into the 

 wood of the tree and oviposit in it). 



Rhyncholus sp. (Blue pine, Spruce, and perhaps Deodar ) 

 Hylastes sp. (Blue pine and Spruce). 

 Diapus impressas Jans. (Qnercus incana). 

 Platypus? sp. (Deodar). 

 All the above are coniferous insects, with the exception of the Dia- 

 pus impressus which bores into the wood of the oak Qnercus incana. 



This Thanasimus would therefore appear to be fairly omnivorous 

 where bark-beetles are concerned, attacking freely many different species 

 and in this resembling its European confrere T.formicarius. 



I think the above short note on its habits will support and confirm 

 the opinion held by the writer, as to the great value and importance of the 

 presence of such an insect in the N.-W. Himalayan Coniferous Forests. 



