THE ENTOMOLOGIST. 245 



Eiibolia rhceniata near York. — On the 19th of August last 

 I took what I thought to be a good variety of E, mensurata, 

 A few weeks ago, upon examining the specimen more closely. 

 I found it answered exactly the description in Stainton's 

 * Manual ' of E. maeniata. I took it by beating broom. — 

 W. Prest, York, in Ent. Mo. Mag., January, 1867. 



[I have been some time in possession of this information, 

 but declined to publish it until Mr. Doubleday had verified 

 the name : has this verification been accorded ? — E. N.] 



Hearing of Decapod Crustacea. — We do not yet tho- 

 roughly understand how they [Crustacea] see, smell, or 

 hear ; nor are entomologists entirely agreed as to the func- 

 tion or the structure of the antennae. 'I'his interesting sub- 

 ject offers a most promising field for study, and I would 

 particularly call the attention of entomologists to a remark- 

 able memoir by Hensen on the auditory organ in the decapod 

 Crustacea. Hensen has shown that the [supposed] otolithes 

 in the open auditory sacs of shrimps are foreign particles of 

 sand, introduced into the organ by the animal itself. He 

 proved this very ingeniously by placing a shrimp in filtered 

 water without any sand, but with crystals of uric acid. Three 

 hours after the animal had moulted he found that the sacs 

 contained many of these crystals. M. Hensen has also 

 shown that each hair -in the auditory sac is susceptible of 

 being thrown into vibration by a particular note, which is 

 probably determined by the length and thickness of the hair. 

 It may be experimentally shown that certain sounds throw 

 particular hairs into rapid vibration, while those around them 

 remain perfectly still. — Sir John Lubbock'' s Address to the 

 Entomological Society of London, Jan. 28, 1867. 



Hearing of Arachnida. — But to return to spiders and the 

 hairs upon their legs ; these vary exceedingly in their form 

 and arrangement, but any minute description of them would, 

 I fear, prove uninteresting, more especially as I should be 

 quite unable to define the particular duty assigned to each 

 kind : there is one exception, however, which 1 shall endea- 

 vour to explain as shortly as possible. Mr. Blackwall says, 

 " Nothing is known with certainty Tioncerning the organs of 

 smell and hearing in spiders." As to the former, 1 have 

 nothing to say ; but I wish to suggest that spiders are 

 capable of distinguishing sounds to some extent by means of 



