THE '/' Efl -A"' ■/ 



insects both with and without ocelli, in addition to the com- 

 pound eyes, and with the Bame results. 



From repeated experiments on fli< . etc., butterfl 

 and moths, dragon-flies and beetles, Plateau concludes that 

 insects with compound eyes <1<> oot notice diff - in 

 form of openings in :i half-darkened room, bul fly with 

 equal readiness to the apparently eaj$ and apparently diffi- 

 cult way of escape; that they are attracted to the more 

 intensely lightened opening, or to one with apparently 

 greater surface; hence he concludes that they cannot dis- 

 tinguish the for t objects, at least only to a very slight 



extent, though they readily perceive objects in motion. 



It is well known that honey-bees on leaving their hi 1 

 fly about as if making out the form of objects near their 

 home, and. after thus taking in the landmarks, can after a 

 few flights make a bee-line from a distance to their hi 

 While this would seem opposed to the result of Plateau's 

 experiments, it ma} be Baid that a very near-sighted man 

 can find his way home; objects even perceived very indis- 

 tinctly serving to guide him. Insects also without doubt 

 distinguish the difference in color of objects; I well known 

 that butterflies will descend from a position high in the air, 

 mistaking white bits of paper Eor white flowers; while, as 

 v. e have observed, white butterflies (Pieris) prefer white 

 flowers, and yellow butterflies (Colias) appear to alight on 

 yellow flowers in preference t<> white on< 



I mil further experiments are made, it seems probable, 



then, that all inserts do not have acute sight, that the;. 



objects best when moving, and on the whole— except dragon- 

 flies and other predaceous, swiftly flying ins h as 

 certain flies, wasps and bees, which have very large rounded 

 eyes insects are guided mainly rather by th< I smell 

 than that of sight. 



Some insects can only detect light from darkness: while, 

 to L r o to the other extreme, a few may see " th cleai 

 and precision, by means of inverted imag< s, either a Land- 

 scape or small neighboring objects." \\ -■ may add with 



