96 



egg, only, in each. The small white larvae grow rapidly 

 and cause the wall of the ovary to develop, and in conse- 

 quence the seed does not form, but the fruit develops into a 

 gall. When the insects are mature they leave the galls, the 

 wingless male first; the females remain somewhat longer. 

 After leaving the ovary they are fertilized by the male. They 

 do not tarry long in the urn. In going out by way of the 

 ostiolum they come in contact with the pollen which is dust- 

 ed over their whole body. They allow their wings to dry, 

 and then run to another urn, either on the same plant or 

 another. In entering a new urn their wings are injured or 

 broken oflF. They leave some of the pollen on the stigmas 

 and when these are in the perfect flowers, seed is developed; 

 but when imperfect, as in those which produce galls, fertili- 

 zation does not occur. It has been observed that although 

 the insect deposits its eggs in the perfect flowers, in Ficus 

 oarica they will not develop, since the ovipositor is so short 

 that it cannot reach the ovule. The caprificus becomes hard 

 and withers on the tree, its only use being to produce pollen. 

 The fruit of the fig tree Ficus becomes sweet and juicy 

 when the seed ripens. The pollination of all species of 

 Ficus have not been studied although for the 600 species de- 

 scribed there are at least fifty species of small wasps belong- 

 in to the genera Blastophoga, Grossogaater, Sycophaga 

 and Tetrapus, which carry pollen from one urn to another. 

 One species, BlastopJiaga brasiliensis, has been found on 

 seven different species of fig tree. Figs will also develop 

 without caprification. 



The willow flower is simple in its structure 



and is usually dioecious. The anthers of 



the staminate flowers usually have some decided color The 



flowers are massed in catkins and open out before the leaves 



