158 Mr. Swainson on several new groups in Ornithology. 



bear the aspect of insects of other orders, and I have a genus, 

 which I call Arachnimorpha^ and io which Atiisonyx cincrca and 

 some others belong, that even resemble spiders. 



N.B. In plate V. figures 3. 4. 5. are given uncoloured, because 

 their sculpture is thus best shewn, and as they are black, or 

 nearly so, the colouring is of no great consequence. 



Art. XV. On several Groups and Forms in Ornitholog?/, 

 not hitherto defined. Bj/ William Swainson, Esq. 

 F.R.S., F.L.S., 4c. 



Notwithstanding the progress which systematic Ornithology 

 has made within the last few years, and the signal benefit which 

 has resulted from the labours of those who have turned their atten- 

 tion to natural groups, there still remains much to be done, before 

 our knowledge of this department of science can be brought to an 

 equality with that which we possess of others. There are, indeed, 

 few striking groups which have escaped the attention of the great 

 reformers of the day; but there are numerous others, which, either 

 from the seemingly trivial nature of their characters, or from the 

 supposed impossibility of detaching them from approximating 

 forms, still remain nearly in the same state in which they were 

 left by the writers of the last century. 



The necessity of a total revision of these geneia, and their sepe- 

 ration into minor groups, is daily becoming more apparent. In 

 pointing out affinities or analogies, we are perpetually obliged to 

 refer to groups " not yet characterized," to explain our meaning, 

 but which, from being undefined, become in fact, no reference at 

 all. Meanwhile new species are pouring in upon us from all parts 

 of the world, which from the same cause are arranged under the 

 old genera, and increase their original confusion. 



To lessen this evil so far as lies in my power, I have long been 

 engaged in revising the characters of all the known groups, and in 



