22 



THE MOUTH-ORGANS, ETC., OF 



In some of the Water Beetles this is carried still farther, the 

 females having their elytra deeply sulcated, as in the genus 

 DytiscuSy and grooved and hairy in Actlius. AVe see how very 

 important this is when we remember that insects, unlike the 

 higher animals, unite but once only ; the male dying very 

 shortly after, whilst the female lives on until she has deposited 

 all her eggs. Nature has provided a receptacle called the 

 spermatheca, in which the seminal fluid of the male is stored 

 up, and it is so arranged as to fertilise each egg before it is depo- 

 sited. The celebrated John Hunter actually succeeded in fertilis- 

 ing the eggs of a female beetle which had not been in connection 

 with the male, by touching them with the fluid which he found 

 in the spermatheca of another female. 



I have tried to point out some of the most important features, 

 as they appear to me, in those beetles of the section Geodephaga^ 

 which I have had the opportunity of examining. Much more 

 might have been written, and doubtless there are many other 

 species which would have proved quite as interesting, or even 

 more so than those I have chosen. In another paper I hope to 

 describe the Larvae of Beetles, and also to contrast the form of 

 the mouth-organs in the Carnivorous Beetles with those of the 

 Vegetable and the Dung-feeding species. 



EXPLANATION OF PLATES I., IL, IIL 



Fi 



g- 



V 



1. — Metoecus paradoxus, $ ; length, one-third of an inch. 



2. — Sitaris muralis ; length, half an inch. 



3. — Claviger foveolatus ; length, one-twelfth of an inch. 



4. — A^iommatus duodecim-striatus ; length, one-sixteenth of an 

 inch. 



5. — Anchomenus alhipes, $ ; length, three and a-half lines. 



6. — Acilius sidcatus, S ; length, five-eighths of an inch. 



7. — Mouth-organs of Nehria brevicollis, dorsal view. 



8. — Ditto ditto ventral view. 



1 



