DISPERSION OF POLLEN BY ANIMALS. 161 



nger in their galls and are there fertilized by the males. Afterwards they come 



it also (c/. fig. 240 ^^), but only stay a short time within the cavity of the inflores- 



snce, issuing from it as soon as possible into the open air. They accordingly crawl 



D to the mouth of the inflorescence, and in doing so they come into contact with 



le pollen of the male flowers and get dusted all over the body — head, thorax, 



jdomen, legs, and wings. After squeezing through between the scaly leaves at 



le mouth of the inflorescence, and having at last reached the outside, they let their 



ings dry and then run ofl" to other inflorescences on the same or on a neighbouring 



ig-tree. I say " run" advisedly, for they but rarely make any use of their wings 



. this act of locomotion. They now seek exclusively inflorescences which are in 



1 earlier stage of development, that they may lay their eggs in the ovaries. 



aving found such an one they crawl to the opening and slip between the scales 



ito the interior. Sometimes their wings are injured in the act of entering, indeed, 



le wings are occasionally broken ofl" altogether, and are left sticking between the 



iales near the aperture. 



Once inside the inflorescence, the wasps immediately devote themselves to laying 



rgs, and in the process are of necessity brought into contact with the stigmas of 



imale flowers. The wasps are still powdered over with the pollen from their 



jthplace, and it is now brushed ofl" on to the stigmas, which are thus pollinated 



om another inflorescence. If the pollen is deposited on normal pistilliferous 



Dwers the latter are able to develop seeds endowed with the power of germination; 



it falls on gaU-flowers it is, as a rule, ineffectual, because the stigmas are more or 



ss abortive. Moreover, no seeds are formed in these gaU-flowers, owing to the 



rgs of the wasp being laid in their place. In those species of Fig in which gall- 



3wers are not specially provided, the eggs are laid in a certain proportion of the 



armally-developed female flowers. It has, however, been observed in the case of 



le Common Fig (Ficus Carica) that eggs of Blastophaga grossorum laid in 



•dinary female flowers do not come to maturity, or, in other words, that a normal 



imale flower is not converted into a gall, even if the wasp in question sinks its 



dpositor into it and deposits an egg in the interior. For the style of the normal 



male flower of Ficus Carica (fig. 240^^) is so long relatively to the ovipositor of 



la^tophaga grossorum, that the &gg cannot be inserted quite into the ovary, but is 



ft at a spot which is not favourable to its further development and there perishes. 



tie gaU-flowers of this species of Fig, with their short styles (fig. 240^*), are, on 



le other hand, pre-eminently adapted to the reception of the egg at the spot where 



le ovule would otherwise develop, whilst at the same time they are not adapted to 



le production of seeds capable of germination, since no pollen-tubes can develop 



Don their abortive stigmas. Evidently we have here a case of complementary 



nctions or division of labour in accordance with the following plan. The wasps 



hich deposit their eggs in the figs carry the pollen both to the short-styled gall- 



)wers and to the long-styled ordinary female flowers, and attempt to lay their 



;gs in both kinds of flower. The gall-flowers are prepared expressly for the 



ception of the wasps' eggs, and young wasps actually develop in them; but their 

 Vol. n. 61 



