260 Insect Architecture. 



cover. They dig, therefore, long tubular galleries between 

 the bark and the wood ; and, in order not to interfere with 

 the runs of their brethren, they branch off from the place of 

 hatching like rays from the centre of a circle : though these 

 are not always in a right line, yet, however near they may 

 approach to the contiguous ones, none of them ever break 

 into each other's premises. We cannot but admire the 

 remarkable instinct implanted in these grubs by their 

 Creator ; which guides them thus in lines diverging farther 

 and farther as they increase in size, so that they are pre- 

 vented from interfering with the comforts of one another. 



[We now come to one or two of the beetles which bore 

 deeply into the very wood of the trees. As a rule, the 

 musk-beetle keeps rather towards the exterior of the tree, 

 but there are many that are not so" cautious, and which 

 besides damage the tree additionally by nibbling a quantity 

 of chips, wherewith they strengthen their cocoons. We will 

 first take the two insects which are shown in the accompany- 

 ing illustration. That on the right hand is a species of 

 weevil, or Curculio, and is an undescribed species belonging 

 to the genus Rhyncophorus. It is a native of Australia. The 

 insect and its cocoon are drawn one third less than their 

 real size. The colour of the beetle is warm chestnut brown, 

 and the bold marks on the thorax are jet black. In its 

 larval state it burrows into the palm-trees, and when about 

 to assume the pupal condition it makes the remarkable 

 cocoon which is figured. Generally, these wooden cocoons 

 are made of little chips which are bitten from the wood, and 

 woven together with silk. This cocoon, however, is made of 

 long fibres, which are torn rather than bitten, and are 'so 

 long that one of them will sometimes encircle the cell three 

 times, making an average length of nine inches. It is 

 tolerably compact in structure, and the colour is pale brown. 



[On the left hand is an opened cocoon of an English beetle 

 belonging to the genus Rhagium. Like the last-mentioned 

 insect, the Rhagium prefers long fibres to short chips, 

 though it does not use them of such a length as the Rhyn- 

 cophorus. The cocoon is generally made between the bark 



