PIN-EYES AND THRUM-EYES 59 



Daubeny, sit up all night, and in the morning report 

 that no moths have visited the primroses. 



Can it be that those ignominious little beetles of 

 the genus Thrips and others that Darwin took such 

 pains to exclude from his experimental plants are 

 entrusted with the important work of fertilising the 

 primrose ? Certainly no insect swarms on any flower 

 as these little beetles do on the primrose. Each tube 

 contains its two or three, and when they come 

 wandering forth on the bunch, very fastidious people 

 deem them a drawback to this otherwise best of 

 spring flowers. But we have only to wait a few 

 minutes, and the tiny creatures spread impossible 

 little pin-points of wings and fly the equivalent of a 

 thousand miles or so to the nearest alluring disc of 

 pale yellow, with its certainty of pollen, either on the 

 first floor or the mezzanine. During the day, at any 

 rate, for one proboscis that enters the primrose tube, 

 at least a thousand little beetles traffic in and out, 

 winging from group to group of the blossoms with 

 long-styled and short-styled pollen clinging to their 

 bodies. 



Thrips, of course, is far too busy and feather- 

 brained a creature to worry about which particular 

 parcel of pollen is to be delivered at which particular 

 stigma, nor does his body serve as a measuring-rod, 

 to be dusted in two rings by the long-styled and the 

 short-styled flowers. But the stigmas are capable of 

 attending to that, if only he will deliver plenty of 

 pollen of each kind. The dust that is indistinguish- 

 able to the unaided eye is widely different under the 

 microscope. There is a difference in size proportion- 

 ate to that between a tennis-ball and a billiard-ball, 



