REPOKT ON ZOOLOGY. 205 



characters of the genera which it comprises, as well as descrip- 

 tions of all the British species*. He divides the class into the 

 two orders of Chilogtiatha and Syng7iatha, the former answering 

 to the Linnsean genus lulus, the latter to that of Scolopendra. 

 This arrangement is adopted hy Latreille. Savi has made a 

 particular study of the luli. In two memoirs, one published in 

 I8I7, the other in 1819f , he has recorded some valuable observa- 

 tions relating to the ceconomy of certain species of this family. 

 I am not aware of any recent contributions to our knowledge of 

 this class excepting a paper by L^on-Dufour on the internal 

 structure of the Lithohius forficatus and the Scutigera lineata. 

 This memoir is published in the Ann. des Set. Nat. for 1824. 



5. Insecta. — It is impossible to do more than to treat of this 

 class in the moat general manner. Indeed from its great extent, 

 the immense additions which have been made to it of late years, 

 and the large number of individuals who have contributed to its 

 progress, it may well deserve to be made the subject of a separate 

 report. I shall simply state, Istly, the leading groups which 

 have been adopted or proposed in this class ; 2ndly, the most 

 important works and memoirs which have appeared in illustra- 

 tion of its structure ; 3rdly, the principal authors who have con- 

 tributed to the advancement of particular parts of it. As the 

 chain of affinities connecting the several orders is far from being 

 determined with certainty, and much difference of opinion exists 

 on this subject, to discuss which would lead to considerable 

 details, I shall be silent on this point altogether. 



(1.) Inthefirst edition of theii^^Tie^wma^thefollowingorders 

 are adopted by Latreille, exclusively of the Myriapoda, which 

 he afterwards acknowledged as a distinct class. 1. Thysanura, 

 Latr.J ; 2. Parasitu, Latr.J ; 3. Suctoria, De Geer ; 4. Coleo- 

 ptera,iAnn.; 5 .Orthoptera,Ol[v.', 6. Herniptera, Linn. ; 7- Neu- 

 roptera, Liinn.; 8. Hy)nenoptera,hmn.; 9. Lepidoptera, Linn.; 

 10. Rhipiptera, Latr. {Strepsiptera,'K\x:h.)', W. Diptera,lAnn. 



In the same year (1817), Dr. Leach published his amended 

 arrangement of the orders of the class Insecta in the third volume 

 of his Zool. Miscellany. In this work we have a primary di- 

 vision into the two subclasses of Ametabolia and Metabolia. 

 The former includes the Thysanura and Parasita of Latreille, 

 the name of this last order being changed to Anoplura : the 

 latter, Latreille's remaining orders, with the five additional or- 

 ders oi Dermaptera, De Geer, (gen. Forficula,'L\im.) ; Dictyo-- 



* Dr. Leach has described several new species of Tultis from the South of 

 Europe in the Transactions of the Plymouth Institution, 1830, p. 158. 

 t See Bull, des Set. Nat., 1823, torn. iv. p. 330. 

 J These two orders were established by Latreille in some of his earlier works. 



