I. TRÄGÅRDH, METAMORPHOSIS AND BIOLOGY OF ORCHESTES. 15 



In some instances however, an elongate, light red-colou- 

 red larva was found in the galleries. The few I found were 

 confined in a glass-tube together with larvse of O. fagi, and 

 I was able to observe that they actually attacked these, and 

 were not inquilines. I succeded in rearing two of them, and 

 they proved to be Nematocera, belonging to the Cecidomyidse. 

 I ha ve not yet been able to get them identified. 



Orchestes quercus L. 



(Pl. I, figs. 13 & 15; Pl. II. figs. 4, 5, 7, 10. 18 & 19.) 



The larva of this beetle was known already by Réaumur 

 [9. p. 31] who gives a figure of it and makes notes on its 

 biology. Låter we find short notes on its biology by Katze- 



BURG, NÖRDLINGER, V. FrAUENFELD a. O. 



In 1908 Mjöberg [5. p. 257 — 63] gives a populär 

 account of its habits, accompanied by drawings of the larva, 

 pupa and fullgrown insect and of leaves attacked by the 

 larva. He has however not been able to observe the mode 

 in which the cocoon is formed. ^ 



The material, on which the following description is based, 

 was collected in June last summer, at Båstad in Skåne. 



The larvse were by no means common on the oaks and 

 I was able to procure only a small number of fullgrown larvse; 

 consequently I am not in position to describe any changes 

 in the external morphology which the larva may undergo 

 during its growth. 



The larva. 



The larva (Fig. 13, Pl. I) is of a white colour, only the 

 head capsule, parts of the prothorax and the small pygidium 

 are of a very dark brown almost black colour. 



It attains a length of 6,5 mm. 



It is of almost even width for the greater part of its 

 length, but the thoracic segments diminish a little forwards 

 and the abdominal segments taper from the 6th one gradu- 

 ally backwards, so that the 8th — lOth together form a cone. 



^ He promises however to investigate the question. 



