APPENDIX. 507 



It will have been observed that, in our letters of Nov. 20 and 27, 1809, 

 a discussion is begun as to what portions of the thorax (Linn.), in the 



XXV. Luminous insects. Mr. SPENCE. 

 XXVI. Hybernation and torpidity of insects. Mr. SPENCE. 

 XXVII. Instinct of Insects. Mr. SPENCE. 



VOL. III. 

 LETTERS. 



XXVIIL Definition of the term insect. Mr. KIRBY and Mr. SPENCE. 

 XXIX. to XXXII. States of insects. Mr. KIRBY and Mr. SPENOE. 



[These four letters were originally assigned to Mr. Spence, 

 and rough copies of them were prepared by him, extending 

 to 120 pages of MS. in large 4to, ; but owing to his ill health 

 (as explained in the advertisement to Vol. III.), the accumu- 

 lation of new matter required the whole to be prepared for 

 the press by Mr. KIRBY.] 



XXXIII. to XXXVI. External anatomy of insects. Mr. KIRBY arid Mr. SPENCE. 

 [This department of the work, as has been previously here 

 explained and in the advertisement to Vol. III., was that to 

 which the authors, both during Mr. Spence's visits to Bar- 

 ham and in their long subsequent correspondence, mainly 

 devoted their attention ; and the tabular view of the parts of 

 insects was the very first portion of the work drawn up by 

 them as the result of their joint examination of a great 

 number of insects of all orders, and of long discussions (both 

 orally and by letter) as to their homological relations : but 

 the more extended and connected survey of the whole subject 

 contained in those letters was drawn up by Mr. KIRBY.] 



VOL. IV. 

 LETTERS. 



XXXVII. to XLIIL Internal anatomy and physiology of insects. Mr. KIRBY and 

 Mr. SPENCE. 



[The explanation given above as to the letters on the 

 states of insects, applies equally to these seven letters on their 

 internal anatomy and physiology. They were originally as- 

 signed to Mr. Spence, whose rough draughts of the letters fill 

 125 MS. 4to. pages ; but it was necessary, in consequence of 

 his ill health, that the whole should be prepared for the press 

 by Mr. Kirby, so as to incorporate the new facts with those 

 which Mr. Spence had collected.] 

 XLIV. Diseases of insects. Mr. KIBBY. 



XLV Senses of insects. Mr. KIRBY. 



XL VI. Orismology, or explanation of terms. Mr. KIRBY and Mr. 



SPENCE. 



XLVIL System of insects. Mr. KIRBY. 



XL VIII. History of Entomology. Mr. KIRBY and Mr. SPENCE. 

 XLIX. Geographical distribution of insects, &c. 



[The first part, on general geographical distribution, by Mr. 

 KIRBY; the remainder by Mr. KIRBY and Mr. SPENCE.] 

 L. Entomological instruments, &c. Mr. KIRBY and Mr. SPENCE. 

 LI. Investigation of insects. Mr. KIRBY and Mr. SPENCE. 

 Appendix. Mr. KIRBY. 



[An enumeration of entomological works, and of papers in 



Transactions, Journals, &c., drawn up by Mr. SPENCE, and 



. extending in MS. to 126 pages large 4to., was unavoidably 



omitted, owing to the much greater bulk of the work than. 



had been originally calculated on.] 



I beg to conclude this long note, which assigns to each, as far as practicable, his 

 share in the work, with a repetition of our desire, expressed in the Preface, and 



Q Q 3 



