SOCIAL WASPS AND HORNTAILS 87 



consist of a number of pairs of woollen trousers. Nothing 

 daunted, however, they set to work upon these also, and 

 pierced them in several directions, as they had previously 

 done the wood, until at last they reached daylight, when, 

 as a rather disappointing reward for their perseverance, 

 they fell into the hands of one of the officers, who was 

 himself an entomologist. 



Like one of the Longicorn beetles before alluded to, 

 this insect has sufficient strength and perseverance not 

 to be hindered in its burrowing operations, even by so 

 formidable an obstacle as sheet -lead, or, indeed, by a 

 still thicker layer of the same metal. Two instances of 

 this have been reported to the Entomological Society of 

 France by M. Lucas. In one instance it was a lead- 

 covered roof that was perforated, the lead being about 

 one-eighth of an inch in thickness. The other was a 

 very curious case. It occurred in an arsenal at Grenoble. 

 A box of cartridges was discovered in which some of the 

 bullets had been pierced by these insects, the explanation 

 apparently being that the larvae had been in the wood 

 of which the box was composed, and that the perfect 

 insects, in endeavouring to work their way out, had 

 directed their course inwards instead of outwards, and 

 had thus encountered the cartridges, through which 

 they had been compelled to eat their way; some of 

 them, however, had perished in the attempt, and they 

 were found dead in the box, with their beautiful yellow 

 bodies blackened with the lead and powder. 



There is an allied species, called S. juvencus, in which 

 the female has a shorter ovipositor, and is entirely of a 

 splendid steel-blue colour. This also occurs in houses, 

 similarly to S. gigas, which it equals in destructiveness 

 as well as in size. Some years ago, no less than two 

 huiidred fir trees were destroyed by this insect on a large 



