Chap A'IL CATASETUM. 207 



stigma of the male Catasetmn, they emitted their 

 tubes. 



The genus Gatasetum is interesting to an unusual 

 degree in several respects. The separation of the 

 sexes is unknown amongst other Orchids, except per- 

 haps in the allied genus Cycnoches. In Catasetum 

 we have three sexual formSj generally borne on sepa- 

 rate plants, but sometimes mingled together on the 

 same plant; and these three forms are wonderfully 

 different from one another, much more different than, 

 for instance, a peacock is from a peahen. But the 

 appearance of these three forms now ceases to be an 

 anomaly, and can no longer be viewed as an unparal- 

 leled instance of variability. 



This genus is stiU more interesting in its manner of 

 fertilisation. We see a flower patiently waiting with 

 its antennae stretched forth in a well-adapted position, 

 ready to give notice whenever an insect puts its head 

 into the cavity of the labellum. The female Mona- 

 chanthus, not having true pollinia to eject, is destitute 

 of antennae. In the male and hermaphrodite forms, 

 namely Catasetum tridentatum and Myarvthus harlatiis, 

 the poUinia lie doubled up, like a spring, ready to be 

 instantly shot forth when the antennae are touched. 

 The disc end is always projected foremost, and is coated 

 with viscid matter which quickly sets hard and affixes 

 the hinged pedicel finnly to the insect's body. The 

 insect flies from flower to flower, till at last it visits a 

 female plant : it then inserts one of the pollen-masses 

 into the stigmatic cavity. As soon as the insect flies 

 away the elastic caudicle, made weak enough to yield 

 to the viscidity of the stigmatic surface, breaks, and 

 leaves behind a pollen-mass ; then the pollen-tubes 

 slowly protrude, penetrate the stigmatic canal, and the 

 act of fertilisation is completed. Who would have 



