398 SYSTEM OF INSECTS. 



Palpi pediform, the anterior pair thickest with 

 a retractile sucker. 



Trunk consisting of two principal segments, 

 with a minute supplementary posterior one 3 . 



Spiracles two placed in the trunk b . 



Pseudo-pectens two c . 



Abdomen divided into segments. 



'Anus unarmed and without a spinning appa- 

 ratus d . 



4-. PHKYNIDEA. 



DEF, Mandibles unguiculate. 



Anterior Palpi chelate or unguiculate e , very ro- 

 bust. 



Posterior Palpi pediform, very long and slender. 

 Abdomen divided into segments. 

 Spiracles two pairs. 



Anus term mating in a mucro, and sometimes in a 

 filiform jointed tail without a sting at the end. 



v. Having considered the Orders into which Insccta 

 and Arachnida may be divided, I am next to give you 

 some account of the groups into which each is further 

 resolvable. To draw out, however, a complete scheme 

 of these would be deviating from my province, and ex- 



a L. Dufour ubi supr. IV. iii. 18. b Ibid. 19. 



c Ibid. t. Ixix./. 7. d. 



When the characters of the Class Arachnida were drawn up 

 (VoL. III. p. 30.) I had not seen a Galeodes : they should be thus 

 amended : 



Palpi four : anterior pair pediform, cheliform, or unguiculate ; 



posterior pediform. 

 Trunk Legs six, &c. 

 PLATE XIII. FIG. 1. 



