Insects on Scotch Firs. 



Insects on Scotch Firs. 



A report was received in February last of an attack upon 

 Scotch fir trees {Pinus silvestris) in Somersetshire, the leading 

 shoots of the branches being seriously injured, and the 

 growth in the case of young trees being materially checked, 

 while some trees looked as if they would not recover. Upon 

 examination it was seen that the larvae of an insect had 

 bored into the stem of the leading shoots, and were feeding 

 upon their sap. The irritation of the larvae had caused a 

 flow of turpentine, which had dried and caked over the 

 larvae. In most cases the shoot was dead or dying. Pupae 

 were also present in some of the holes made by the larvae, 

 ensconced in slightly woolly cocoons. It was at first con- 

 sidered that the insect was Cecidomyia {Diplosis) fiini, as the 

 larvae and pupae were somewhat similar, and the position 

 and appearance of the cocoons were similar to those of this 

 Cecidomyia. The pupae were, however, preserved, and on the 

 20th of March flies came from them which Dr. Meade, the 

 w T ell-known dipterist, pronounced to be Oscinis Maura. This 

 fly differs in shape and colour from Cecidomyia pint, which 

 causes somewhat similar injury to fir trees. It is very dark 

 with a decided green shade, has brown wings, reddish legs, 

 and black femora and tibiae ; it is about the eighth of an 

 inch long. The larva is less than the eighth of an inch 

 long, of yellowish colour and cylindrical shape, without 

 legs, and has a strong pair of hooked jaws well adapted for 

 biting. The pupa is not so long, and rather darker in colour. 

 It is said to be a fairly common insect. Meigen, who calls it 

 Chlorops maura, though he assumes it to be the same insect 

 as Oscinis maura (Fallern), says it is very common, and that 

 the fly appears in May, and may be seen in meadows.. 

 Macquart also states that it is found in meadows. Nothing 

 can be ascertained as to the state in which this insect passes 

 the winter. As larvae w^ere found active and feeding in 

 February, it might be concluded that it remains in the larval 

 condition during the winter; but it should be noted that 

 there was no cold weather in the last winter, so that this 

 state of the insect may have been abnormal, and, like other 

 species of the Oscnrides, it may, perhaps, usually pass the 



