Februaiv— March iSSo.l 



PSYCHE. 



17o 



Leave cannot be taken of the extra- 

 nuptial nectar of phaenogams and ferns 

 without reference to the sugary exudation 

 which escapes on the emission of sper- 

 matia of Uredineae. As was shown by 

 Rathay (23), this is greedily devoured by 

 ants and other honey-loving insects. But 

 the senice that these i"ender, if any is 

 rendered, is not clear, since it is not cei'- 

 tain whether the spermatia are spores or 

 male reproductive cells, though there is 

 reason forconsideringthem to be spores.* 

 That ants play a considerable part in scat- 

 tering these bodies is a necessary a /r/or/ 

 conclusion ; but it is not so evident how 

 far the secretion of a sugary fluid is to be 

 regarded as an adaptation to this end. 

 It has recently been explained by Lud- 

 wig (15) in accordance with the Del- 

 pi no- Belt theory. 



2. occasioxai, axt -domiciles on 

 Plants. 



Some part of a plant is not infre- 

 quently tenanted by ants which find 

 there shelter or food to their liking, but 

 so far as our own and other temperate 

 floras are concerned, there appears to 

 be no adaptation by which the plant is 

 fitted to maintain or especially profit b}- 

 this residence of ants. The heart-wood 

 of some of our forest trees is often in- 

 habited in this manner by the large 

 black ant, Formica pctinsylvanica. On 

 several occasions I have also found an 

 undetermined small brown ant nesting 

 in the old hypanthia of Calycaitthus, 

 still adhering to the plant, in the botanic 



* See Plowright, managr. of British Uredineae and 

 Ustilagineae, 1S89, 11 et seq. 



garden at St. Louis. No doubt any 

 close observer of the ways of ants can 

 add mam- instances of the same general 

 character, in which, so far as the biol- 

 ogy of the plant Is concerned, the ants 

 are merely accidental residents, though 

 their pugnacity may lead them to resist 

 the attacks of other creatures whose 

 presence is distasteful to them. 



It is also known that ants sometimes 

 construct somewhat elaborate nests on 

 plants. Some cases of this sort are 

 noted by Westwood (34, 222) and Pack- 

 ard (21, 317). and I presume that a 

 person more familiar than myself with 

 entomological literature could cite other 

 references on this subject. Several years 

 ago I contributed to the Club the gist 

 of observations on a colony of Crema- 

 tog-aster which had erected a nest 

 over their wards, certain aphides, on a 

 branch of Andromeda., where they ap- 

 parently spent their entire time (Psyche, 

 V. 3, 31). Similar nests had been ob- 

 served before bv others(Psyche,v. 3, 343 ; 

 and the Minutes of the meetings held dur- 

 ing 1 883, 2) . In the case observed by my- 

 self the ants appeared to be kept at their 

 post bv the aphides (which they may 

 themselves have placed upon the plant) , 

 and the shelter was eA'idently constructed 

 as much for these Insects as for them- 

 selves. Where ants protect the enemies 

 of a plant In this manner, they are clearly 

 injurious to it in the first place, though 

 thev may at the same time keep oft" others 

 of Its enemies In endeavoring to guard 

 their proteges. The good may even 

 more than counterbalance the harm done, 

 and Lundstrom has suggested that in 



