280 PROTECTION AGAINST INSECTS. 



Abdomen with 5 segments. Generation usually biennial. 



Larvae soft, white or yellow, usually cylindrical, rarely some- 

 what flattened, with projecting broad thoracic segments, of 

 which the first at least is furnished above with a horny plate. 

 Their feet consist of six minute tubercles, or are entirely 

 absent. 



Pupae fusiform, and recognisable by the long horns bent 

 down in a curve from the head. 



Flight-holes transversely oval. 



The larvae generally live under bark and in wood, but 

 usually only in broken trees or in stumps ; a few species are 

 found in beams of houses. Their attack is of a secondary 

 nature, as they bore into trees killed by bark-beetles and other 

 insects, but on account of the large size of their galleries, and 

 the quantity of boring dust which exudes, it easily attracts 

 attention. 



On sunny days the beetles may be found on flowers, shrubs, 

 and felled trees ; the females do not make mother-galleries. 



Longicorn beetles are rare as a rule in the British Isles, and 

 most of the species found are small and of little or no economic 

 importance. In tropical countries they play an important part 

 in the destruction of fallen and decaying timber. 



1. Saperda carcharias, L. (The Large Poplar Longicorn.) 



a. Description. 



a b 



Beetle 23 to 30 mm. 

 long, grey or brownish 

 yellow, dotted with 

 many shining black 

 points. Thorax short 

 and cylindrical. Elytra 

 with the shoulders 

 prominent, narrowed 

 posteriorly and bluntly 

 spined at the apex. 

 Fig. ns.-Saperda carcharias, L. Larva extending up to 



a Imago. i> Larva. 36 mm. in length, with- 



out legs, cylindrical, 

 yellowish white, with the mandibles and segmental shields 



