550 



Marvels of the Universe 



Phnlo htil l/iKgli Main, Zi.,Sf., F.E.fi. 



THE TORTOISE BEETLE. 



Similarity to its surroundings and an appearance of 

 rubbish also characterize the chrysalis stage. 



/■//oM hii'\ [Hugh .V„LH. /;.,'c., F.E.X. 



THE TORTOISE BEETLE. 



It is from the appearance of the perfect insect 

 that the beetle gets its name. European specimens 

 are chiefly dull green and brown, but fo 

 varieties are brilliant as jewels 



foreign 



In due course, from the eggs the young larvae emerge, 

 and these are strange and weird-looking little animals of 

 extraordinary habits. The structure of the beetle itself 

 is curious, but that of the larva is still more so. Like its 

 parents, it is green in colour, while its body is both 

 broad and flattened. Its fore-parts are much larger than 

 those which follow, and around its margin is a row of 

 curious spines beset with tiny bristles. At its tail-end, 

 which is slightly upturned, appears a forked appendage 

 which turns over its back, extending nearly to its head. 

 These details of structure are, of course, difficult to see 

 in the earliest stages of the larva, but later on they 

 become more obvious, and it is then that we begin to 

 realize what a strange animal it is. 



In the first place, it is apparent that these insects 

 have in the course of their evolution been subjected to 

 the attacks of insectivorous foes. The green colour of 

 the beetle, its flattened form, and its consequent incon- 

 spicuous appearance, are undoubtedly features of a pro- 

 tective character. Then, in the case of the larva we find 

 analogous characteristics. Here also the protective green 

 colour is again utilized, and the bristly spines are a 

 feature associated with unpalatableness. Furthermore, 

 there is the curious forked apparatus at the tail, which is 

 directed over its back ; what useful purpose can that 

 serve ? 



When the larvae commence to feed, the function of 

 that organ becomes obvious, for then we find it quickly 

 converted into a dark-coloured umbrella, under which the 

 larva is almost hidden from view. This canopy is the 

 more remarkable when we consider how it is produced, 

 for it is nothing more than the waste products of the 

 body, which, instead of being rejected, are gathered and 

 stored for this purpose, only occasionally being thrown off, 

 when a new layer is quickly produced. 



At first glance it appears that the larva is necessarily 

 living under most unsavoury conditions ; but we have to 

 remember that the process of digestion in leaf-feeding 

 larvae is different from that of the higher animals. Only 

 the juices of the leaf are required, and the digestion 

 consists rather in the grinding and crushing of it to 

 obtain its juices, than in actually digesting it. Con- 

 sequently, the leaf particles which pass through the 

 digestive system of the larva, if softened in water and 

 examined by the microscope, reveal the leaf tissues 

 almost in their entirety. Therefore, when exposed to the 

 air, these leaf particles quickly dry and form a covering 

 which is scarcely more offensive than crushed particles 

 of dry leaves would be. 



