194 



Marvels of Insect Life. 



Pholn by H. Mam, f.E.S. 



Egg of Musk- 

 Beetle. 



The musk-beetle lays her 

 eggs in crevices of old 

 willow-trees, where pro- 

 bably there are many holes 

 and tunnels testifying to 

 the attacks made by several 

 generations of its kind 

 upon the wood. The egg 

 above is magnified four 

 times. 



glories in the sunshine. Our nearness to them may be first inli: 

 mated througli our sense of smell, by the odour of sweet-briar giveo 

 off by them. Then the eye catches sight of the brilliant colouring 

 as the sunlight falls upon them. The reason for these musk- 

 beetles being upon the willow-tree is that they were bred from its 

 interior, and have to prepare for another generation of their kind 

 continuing the work they have been doing. So they will lay their 

 eggs in its crevices, and when these are hatched the young grubs 

 will bore into the wood and make galleries, right into its heart 

 may be. It is a yellowish- white, fleshy grub, rather ffat above 

 and below. When fully grown it is about an inch long, broadest 

 just behind the very small head, from which it tapers slightly 

 behind. Though its head is small, its little jaws are effective 

 instruments for breaking down the wood-tissues, and making them 

 available for food. As their grub-stage extends over two or three 

 years, their burrows are often of considerable length. They 

 appear to follow no definite course, and often extend far in. 

 xA.s a number of larvae attack the same tree, it becomes fairly 

 riddled, and this often brings about its decay, although the willow 

 can endure much ill-treatment without being killed. When the grub has reached 



its full size it enlarges part of its burrow 

 and forms a sort of cocoon of wood 

 fragments, and there changes to a 

 chrysalis, from which the perfect beetle 

 emerges in June or July. 



The tropics afford us gigantic 

 examples of these long-horned beetles, 

 which are all wood-borers in the grub 

 stage ; but although these exotics make 

 imposing features in our museums, and 

 have had cqualU' imposing scientific 

 names bestowed upon them, scarcely 

 anything is known of their life-histories, 

 the collectors who have been sent out 

 after them being more concerned in 

 making a " good bag," than in getting 

 information. Of several of them, 

 however, something is known which 

 enables us to judge that the habits are 

 pretty much alike throughout the 

 family. Among these large beetles are 

 the titan * of the Amazon region, whose 

 grub attacks the largest trees, and the 

 Indian sawhorn,'^ whose jaws are of 

 such a size as to remind one of those of 



Acanthophorus serraticornis. 



Photo hy\ 



H. Main, F.li.S. 



Grub of Musk-Beetle. 



For two or three years the grub of the musk-beetle feeds upon the 

 wood of the willow, and makes long galleries in doing so. When 

 full grown it enlarges part of its bunow and forms a nest of wood- 

 cliippings, and becomes a chrysalis. 



1 Titanus giganteus. ^ 



