EXTERNAL ANATOMY OF INSECTS. 461 



the upper sides of which emerge a pair of moveable or- 

 gans terminating in a powerful incurved claw, and which 

 entirely covers all the other parts of the mouth a . This, 

 M. Savigny deems as a second auxiliary labium, and the la- 

 teral organs of prehension,— which may be regarded each 

 as a kind of maxillary hand, and as the only representa- 

 tives" in this tribe of the maxillary palpi, though widely 

 different, — he looks upon as really analogous to the second 

 pair of legs in lulus and the hexapods b . These two pairs 

 of pedipalpes (to use an expressive French term) show 

 their relation to legs by their general structure, and their 

 analogy with palpi by their use as oral organs, though 

 belonging to the trunk : so that here we see the legs and 

 their appendages assume a material function in mandu- 

 calion, forming a singular contrast to what we had ob- 

 served before with regard to mandibles becoming instru- 

 ments of locomotion. The mouth of the Iulidce, with lit- 

 tle variation, is upon the same plan c with those here de- 

 scribed. 



The next type of form with regard to the oral organs 

 is that of the Arachnida. In these, as you know, the 

 head is confounded with the trunk ; so that they are a 

 kind of Blemmyes in the insect world. Their organs of 

 manducation, amongst which there is no labrum or upper 

 lip, are, in the first place, a pair of mandibles planted 

 close and parallel to each other in the anterior part of 

 the head, which they terminate. In the spiders they con- 

 sist of two tubular joints, of which the first is much the 

 largest, more or less conical or cylindrical, and armed 



a Plate VII. Fig. 11./', a . b Ubi supra, 45. 



«= Ibid. 44—. 



