COCOON OF THE RHAGIUM. 201 



Rliagium tlie body is rather flattened, and there is a sharp 

 spine at either side of tlie thorax. The word Ehagium is a 

 Greek one, and signifies a little berry. 



There is not the least difficulty in distinguishing the present 

 species. The colour is blackish, but the surface is covered 

 with a very fine yellowish down, and is thickly punctated. 

 The elytra have an elevated line, or rib, running longitu- 

 dinally along them ; and upon the middle, or disc, there are 

 two irregular reddish-yellow bands, placed as shown in the 

 Illustration. During its larval existence this insect lives in 

 decaying ash and willow-trees, and may be dug out of them in 

 spring, and found on and about them in summer. 



There is another species, not so common as the former, 

 which inhabits decaying fir-trees. Only a short time before 

 writing this account, I dug several of them out of some fir- 

 stumps near my house. In one small stump, not more than 

 seven inches in diameter, I found four specimens. The name 

 of this species is Rhagium hifasciatura. It is marked much 

 as is the preceding insect, but may be known by a conspicuous 

 groove along the top of the head, and the fact that tlie elytra 

 have three longitudinal ridges instead of one. The yellow 

 bands, too, are shorter, and the colour both of these and the 

 elytra is exceedingly variable. 



It is a remarkable fact that these insects invariably assume a 

 perpendicular position before changing into the pupal form. 

 They may always be found with their heads upwards, and their 

 antennae and legs packed closely against their bodies. Their 

 behaviour when the light is allowed to shine on them is rather 

 variable, and depends much on the weather. Should the day 

 be a warm one, the Rhagium seems glad to escape, and 

 struggles hard to free itself from the decaying wood with which 

 it is surrounded ; but on a cold day, especially if there be a 

 sharp wind, the insect retreats as far as possible into its curious 

 nest, and tries to shelter itself alike from wind and light. 



The nest, or cocoon, which the Beetle makes is a very 

 curious one. Just before it undergoes its change into the pupal 

 form, it prepares an oval chamber, and within this chamber 

 makes a cocoon from rather long wood-chips, which it arranges 

 with great art, so as to form a soft bed in which it can repose 

 during the long period of quiescence. It is not easy to procure 



