Fertilisation of Epipactis latifolia. 349 



naturalists are under the belief that this E2npact{s is 

 constantly fertilised by this insect, one indeed going so 

 far as to say that if wasps were becoming extinct in any 

 locality, so, in all probability, would Epipactis latifolia.) 

 On other occasions, however, I did see the common wasp 

 visit several flowers, but the visits were short, and, if I 

 may use the expression, heartless, as if it could derive 

 little therefrom. Owing to their long narrow shape and 

 short proboscis, wasps remove the pollen masses with ease, 

 for I have caught them immediately after coming out 

 of the flower with the pollinia attached to their head ; but 

 as these visits are few and far between, fertilisation by 

 this way is of rare occurrence. In numerous instances, 

 also, the pollen masses will be found glued to the upper 

 sepal of the flower, which is done as follows : — The 

 wasp on entering, particularly a newly-opened flower, 

 gets the pollinia attached to its head when sucking the 

 nectar; but immediately on entering another flower, the 

 upper sepal is so situated that the sharp stiff edge comes 

 in contact with the viscid substance, which, with the 

 pollinia, is left attached to it. This, I have never seen 

 take place, but repeated experiments bear out the state- 

 ment. It is also readily illustrated with a pencil. In 

 various other parts of the plants it is not uncommon to find 

 the pollen masses attached as if the discs were not suffi- 

 ciently viscid to retain their hold on the insect's head, 

 and on more than one occasion I have found them unbroken, 

 on their stigmatic surface. Small insects also visit the 

 flowers in numbers, as I have watched them creeping about 

 wnthiu the labellum and other parts ; but in numerous 

 instances many of those which come in contact with the 

 viscid, stigma are unable to free themselves, and so perish. 

 The largest insect that I have seen killed in this way was j\ 

 of an inch in length. When the plants begin to wither, or 

 immediately after fertilisation takes place, the distal portion 

 of the labellum curves upwards, and effectually closes the 

 entrance to the basal portion or nectary, but for what end 

 I am unable to say. 



3, That self-fertilisation by the pollen falling spon- 

 taneously on the stigma is not uncommon. I have 

 frequently observed that the pollen masses in a few days, 



TRANS. EOT. SOC. VOL. XVI. 2 A 



