i9i i.] The Alder and Osier Weevil. 



215 



(2) The grub gnaws a gallery in the wood. Tunnelled 

 branches break across, and are blown down by the wind. 



(3) The adult punctures the bark, and gnaws the bark of 

 branches right into the cambium. Such wounds afford 

 suitable places of entry for the spores of some injurious fungi 

 that are wound parasites. 



(4) The tips of shoots are eaten so that the shoots bend 

 over, fail to elongate, and die. 



(5) The bark undermined and tunnelled by the larvae dies, 

 sinks in, and ultimately crumbles, exposing the sapwood. 



Symptoms of Attack. — (1) The yellowing of the leaves, and 

 the gradual withering of the shoot. 



(2) The change in colour of the bark just above the feeding 

 place of the young larva. 



(3) The sawdust that is sent out from the larval gallery. 

 This sawdust and the thread-like spales of wood, from the 

 gnawing of the larva, may remain on the outside of the bark 

 round and below the external bore-hole, sticking together in 

 a clump; this material may also fall to the ground below. 



(4) The canker-like places on the outside that result from 

 larval attack. 



(5) The round flight holes of the adult beetles. 

 Description. — Adult: The beetle measures about J inch in 



length; it is dull black or black-brown in colour; the pro- 

 thorax, the sides of the thorax, the hind third of the wing- 

 covers, and the thighs are more or less thickly covered with 

 chalk-white or yellow-white, or sometimes reddish-white 

 scales; the antennae are reddish, and clubbed at the apex; 

 the rostrum or proboscis is well marked, but when the beetle 

 is at rest the proboscis cannot be seen well from the upper 

 surface owing to its being bent under the thorax ; the wing- 

 covers (examined with a lens) show a series of longitudinal 

 lines and punctures, and erect tufts of black scales. The base 

 of the wing-covers is square, but the apex is narrowed. 



Larva: The larva is a legless grub with a whitish body and 

 brown head and mouth parts. 



Pupa: The pupa is yellowish-white, and lies in the larval 

 gallery, with bent proboscis. 



Life History. — The adult beetles are found from May 

 onwards during the summer. The female lays her eggs 



