192 EYES OF CRUSTACEA AND INSECTS. 



property; and of all British insects, the Common 

 Death's-head Moth is perhaps the most con- 

 spicuous in this respect. Either by daylight, or 

 when the rays from a candle fall upon the eyes, 

 they glow as if lighted from within by some hidden 

 fire j a circumstance which adds in no small 

 degree to the terror which is often inspired in 

 the uneducated mind at the sight of one of these 

 insects- In all cases the light departs together 

 with the life of the animal : its origin is not as 

 yet clearly ascertained. Even the eyes of the 

 common Dragon-fly, a diurnal insect, possess a 

 kind of fiery glow when viewed during the life of 

 the creature, but turn to dull, dead hemispheres 

 as soon as it perishes. The light that is reflected 

 from the eyes of cats, &c. is accounted for on 

 principles that do not hold good with regard to 

 the compound eyes of insects or Crustacea. The 

 ordinary edible prawns are not found between 

 tide-marks, except occasionally when an unhappy 

 individual has been driven towards the shore, and 

 has not been able to regain the sea before the 

 waves have retired. For this creature, the 

 shrimping net or the dredge is requisite; and 

 as it is tender in constitution, a vessel of sea- 

 water should be ready for its reception when 

 taken out of its native haunts. 



