34 [February, 



A CONTEIBUTION TO THE LIFE-HISTOEY OF PIEZODORUS 



LITURATUS L. 



BV E. A. BUTLER, B.A., B.Sr., F.E.S. 



Piezodorus lituratus L. is one of the fominouest of our British 

 Pentatomidae, a,iid is found on furze bushes in most places where these 

 flourish ; but, though it is a common insect, very little has been re- 

 corded as to its life-history and general habits, and the following is 

 an attempt to summarise what has up to the present time been ascer- 

 tained. 



In every instance that has come under my notice, the eggs have 

 been laid on the young and unopened, but fully-formed, flower- buds of 

 the furze (Ulex evropaeus), being placed in a double row along one of 

 the two sepals. Each group contains from eleven to fourteen eggs, 

 placed in two contiguous rows ; those in each row are in close contact 

 with one another, and are placed alternately to those in the other ; 

 when there is an odd egg it is set in the middle line at one end. The 

 egg is a drum-shaped body, consisting of a short cylinder rounded at 

 the end which is attached to the flower, and somewhat flattened at the 

 other, where it is closed by a kind of lid. The whole surface is banded 

 alternately with rings of white and nigro-fuscous, a white spot form- 

 ing the centre of the distal extremity, and a dark one that of the 

 proximal, while the sides show two white and two dark bands. The 

 sui'face is reticulated and beset all over with tine whitish spines ; and 

 further, the white band round the apical rim carries a series of about 

 30 large white spines, which are strongly clavate and nearly erect. 

 The circular lid is of the same texture as the rest of the shell, and is 

 white, with a not very clearly defined nigro-fuscous ring on its disc. 



On hatching, this cap is pushed up on one side, remaining attached 

 at the opposite point, so that after the emergence of the larva, it falls 

 back almost into its original position. It does not, however, quite close 

 the aperture, because there usually projects a ciirious apparatus which 

 has been well described by J. H. Fabre in connection with nnother 

 species {Souv. Ent., viii, 69). This consists of a clear membrane with 

 three strong bro"wnish ribs radiating from one point on its margin, 

 like the webbed foot of a duck. According to Fabre, this apparatus 

 is general in the Pentatomidae, and is used in conjunction with the 

 forcing of blood into a trihedral vesicle on the head, as a spring to 

 push open the lid of the egg ; and it remains, after the emergence of 

 the insect, projecting through the opening, and preventing the lid 

 from being completely shut. (Fig. 1.) 



