166 : THE ORCHID REVIEW. [Nov.-DrEc., 1920. 
VERY interesting discovery respecting the fertilisation of Ophrys has. 
been made by M. Pouzanne, President of the Court of Justice at Sidi 
Bel Abbas, Algeria, who for more than twenty years has studied the genus 
with respect to the fertilisation of the flowers. The result of M. Pouzanne’s 
observations are given in a rather long paper, in collaboration with M. 
Henri Correvon (Journ. Soc. Nat. Hort., 1916, pp. 29-31, 41-47), of which 
the following is a summary. 
Darwin admitted that he could not understand the fertilisation of Ophrys, 
for the flowers offered no inducement to insects to visit them, yet by their 
very structure they were clearly intended for insect fertilisation. In alluding 
to the well known fact that the flowers of Ophrys bear a rude resemblance 
to bees, flies, &c., it is interesting to seek the reason of this strange mimicry. 
But observation of the insect visitors is difficult, and requires much patience 
and perseverance. In the case of the species under review, the fertilising 
insects appear to be the males of certain small burrowing hymenoptera, 
which emerge some time (one to four weeks) before the females, and fly here 
and there awaiting their appearance. It is during this interval that, in calm 
sunny weather, fertilisation chiefly takes place, and the period may be 
shortened by exceptional circumstances which hasten or retard the 
appearance of either the flower or the insect. Lastly, it is necessary that 
the insect colonies be sufficiently near the places where the plants grow, for 
the males will not forsake the ground where the females are still dormant. 
As these conditions must be in agreement before fertilisation takes place, 
it isnot surprising that less than a fourth of the flowers may produce 
capsules, and that observations are difficult. In practice, it is little use 
attempting observation unless many plants are flowering together; it is only 
waste of time observing isolated specimens. 
_ If one is blessed with good eyesight, it is possible to distingiush among 
the small insects which fly near the Ophrys those which are bearers of 
pollinia, and with a little practice it is possible to recognise the fertilisers i 
flight. From present observations it would appear that the species of 
Ophrys may fall into two categories, those that have a fairly deep cavity a 
the base of the lip (O. fusca and O. lutea), and those without a cavity (O. 
speculum), these being the only three species in which the fertilisation has 
been personally observed. 
O. speculum has been observed in several Algerian localities, and for a 
period of twenty years. It is fertilised by the male of the hymenopterous 
insect, Colpa aurea, much like a slender bee, and having its elongated body 
|@| FERTILISATION OF OPHRYS. 
B 
| die 
