168 



ME. D. SHARP ON THE EESPIKATORY 



No. 2. Sept. 12th, — At 4.5 p.m. took my station at the side of 

 tlie vase containing the female H. ovatus. It appeared at the 

 surface at 



4.12, resting there 15 seconds. 

 4.21 „ ,. 25 



4.45, resting there 3 seconds. 

 5.17 „ ,. 10 ,. 



Observation ceased at 5.45 p.m. The insect carries a bubble 

 at tip of body, which, by movements of the segments, is some- 

 times retracted under elytra and again exserted without being 

 detached. 



No. 3. Commenced observation same night at 9.19 by arti- 

 ficial light. The beetle rose at 



sec. 9.51, remained up 3 seconds. 



9.57 „ „ 20 „ 



9.58 „ „ -t 



10. 3 „ „ 10 seconds. 

 10. 9, observation ceased. 



No. 4. Sept. 26th. — I watched for one hour from 1.31 p.m., but 

 the female in question did not issue from her hiding-place. 



No. 5. — 9 P.M. by lamplight. Beetle concealed, and did not 

 emerge till 10.2. It then rose to the surface for the purpose of 

 aeration for 3 seconds, and rapidly repeated the process, thus : — 



10.2, at surface 3 seconds. 

 10.3 „ 5 



10.3 „ 4 „ 



10.3 „ . 5 „ 

 10.5 „ 3 



10. 7, at surface an instant. 



10. 8 



10. 9 



10. 9 „ 10 seconds. 



10.11, observation ended. 



It is probable that its aeratory process was considerably inter- 

 rupted by the disturbance of the artificial light ; and hence the 

 ^bove rapid ascents and descents. 



* Within the time mentioned in the bracket the Hyphydrus descended for 

 an instant — that is, darted down and up again. 



t When it rose to the surface at the hour specified, it remained there motion- 

 less for a minute or more, but did not then seem to perform aeration. I pre- 

 sume that the insect was incommoded by the artificial light. 



