THE ENTOMOLOGIST. 



Nos.l21&l2a.] OCTOBER, MDCCCLXXIII. [Pbice Is. 



Oti the Brain and a Portion of the Nervous System of 

 Pediculus Capitis. By J. S. Bowerbank, LL.D., F.R.S. 



About twenty years ago Mr. Topping furnished me with 

 one of the finest preparations in Canada balsam of a specimen 

 of Pedicuhis Capitis that I have ever seen. It possesses 

 great transparency, and, at the same time, by the mode of 

 preparation, the muscles and nerves are stained of an amber- 

 yellow colour, so as to be rendered distinctly and beautifully 

 visible beneath the microscope. The examination of this 

 specimen at the time I received it disclosed so many inte- 

 resting facts appertaining to the brain and nerves of the 

 creature, that 1 felt a strong inclination to carefully examine 

 its organization, in the hope of throwing some additional 

 light on the anatomy and physiology of insects in general, 

 and on the organs of sense and the habits of this one in 

 particular ; but other occupations have hitherto prevented me 

 from pursuing this subject until the present time. 



The brain varies to a considerable extent in size and 

 form in different tribes of insects, but in this one it is a more 

 than usually well-developed state. The two lobes of the 

 cerebrum are united at the upper surface of the organ, but 

 they are widely separated beneath and between the separated 

 portions ; the oesophagus, deeply embedded, passes from the 

 anterior to the posterior parts of the head over the upper 

 surface of the cerebellum, which is gradually inclined down- 

 ward from its junction with the posterior portion of the 

 cerebrum. A partial constriction of the general mass marks 

 the junction of the posterior part of the cerebrum with the 

 anterior portion of the cerebellum. The fore part of the 

 cerebellum closely resembles the cerebrum in form, but it 



VOL. VI. 2 a 



