244 THE ENTOMOLOGIST. 



the lar\'aB of which live in the interior of the branches of the 

 willow. I must premise that I am unacquainted with the 

 larvae themselves, and I begin to fear it may be years before 

 I have an opportunity of seeing them, even if I ever do so ; 

 it seems to me that for their belter recognition it may be as 

 well to publish the description of this species after that of 

 the sawfly inhabiting the leaf. I was the more unwilling to 

 keep back the description of Lugdunensis until I had met 

 with these larva, as it is uncertain whether the latter of the 

 two pith-dwellers occurs in the Netherlands, a fact which 

 does not appear from the description by De Geer. By the 

 kindness of Mr. C. Ritsema I received two individuals of 

 Cryptocampus angustus, a dead male, and a living female, 

 with the twigs in which were the cocoons, and in which the 

 insects had undergone their metamorphosis. The twigs con- 

 sisted of the top ends of the common willow {Salix cinerea) ; 

 they had been cut off' in the neighbourhood of Oegstgeest, and 

 because there was a hole in one of them they had been 

 opened, one being found to contain a part of a cocoon. At 

 the time they were cut off it was rather cold — it was in the 

 month of March — and there was, consequently, no immediate 

 prospect of the insects inhabiting them making their 

 appearance. 



The cocoon found in the hollowed-out pith of one of the 

 branches was cylindrical, with rounded ends, its substance 

 being thin but tough ; the colour was pale purplish brown. 

 I am unable to determine whether the larvae had fed on the 

 pith of these willow-twigs during their whole lives, or 

 whether they had hollowed out the pith merely for the pur- 

 pose of spinning up. According to what Dr. Hartig states, 

 it might be assumed that the larva had inhabited the interior 

 in the earlier stages of its existence instead of first feeding 

 upon the leaf This point, must thus be left for determina- 

 tion by future entomologists. The following is a description 

 of the two sexes : — 



Male. — Length, five millimetres. Shining black, glabrous. 

 Head but slightly prominent, broad, with two grooves an- 

 teriorly along the eyes, hollowed out posteriorly ; eyes pro- 

 jecting, these latter black and shining. Trophi brownish ; 

 the margin of the labrum hairy ; mandibles black at the tips, 

 palpi fuscous. Antennae two-thirds the length of the body 

 and moderately thick ; the first two joints black, the remain- 

 ing joints dark brown on the upper side, pale brown on the 

 under side ; on the last joint (the ninth), there is a small bent 



