MOTIONS OF INSECTS. 



239 



II. I am next to say something upon the motions of insects 

 in their pupa state. This is usually to our little favourites a 

 state of perfect repose ; but, as I long since observed, there 

 are several that, even when become pupae, are as active and 

 feed as rapaciously as they do when they are either larvae or 

 perfect insects. The Dermaptera, Orthoptera, Hemiptera, 

 many of the Neuroptera, and the majority of the Aptera, are 

 of this description. With respect to their motions, we may 

 therefore consider pupae as of two kinds — active pupae, and 

 quiescent pupae. 



The motions of most insects whose pupae are active are so 

 similar in all their states, except where the wings are con- 

 cerned, as not to need any separate account. I shall therefore 

 request you to wait for what I have to say upon them, till I 

 enter upon those of the imago. One insect, however, of this 

 kind, moving differently in its preparatory states, is entitled 

 to notice under the present head. In a late letter, I mentioned 

 to you a bug {Reduvius personatus), which usually covers it- 

 self with a mask of dust, and fragments of various kinds, 

 cutting a very grotesque figure. Its awkward motions add 

 not a little to the effect of its appearance. When so disposed, 

 it can move as well and as fast as its congeners ; yet this does 

 not usually answer its purpose, which is to assume the ap- 

 pearance of an inanimate substance. It therefore hitches 

 along in the most leisurely manner possible, as if it was 

 counting its steps. Having set one foot forwards (for it moves 

 only one leg at a time), it stops a little before it brings up its 

 fellow, and so on with the second and third legs. It moves 

 its antennae in a similar way, striking, as it were, first with 

 one, and then, after an interval of repose, with the other. 1 

 The pupae of gnats also, as well as those of many other aquatic 

 Diptera, retain their locomotive powers, not, however, the free 

 motion of their limbs. When not engaged in action, they 

 ascend to the surface by the natural levity of their bodies, 

 and are there suspended by two auriform respiratory organs 

 in the anterior part of the trunk, their abdomen being then 

 folded under the breast ; when disposed to descend the animal 



De Geer. iii. 284. 



