NECTAR AND ITS USES.. 327 



ta,r was to secure protection to the flowers, rather than to secure their 

 fertilization, though the latter might occasionally occur incidentally. 



On the lower surface of the leaf of the cotton plant, not far from its 

 base, the mid-rib bears a large sunken nectar gland, and each of the lat- 

 eral veins of the larger leaves bears a similar gland.* Traces of these 

 glands may sometimes be found on the cotyledons, but I never saw a 

 perfect gland on a seed-leaf. As shown by the visits of ants, the gland 

 of the first leaf begins to secrete when the seedling plant has about four 

 leaves expanded; but it is not till some days later that enough nectar is 

 produced to be noticeable, and from this time on the gland secretes 

 abundantly until the leaf becomes old or diseased. When a gland is in 

 vigorous secretion it may be examined at almost any time of the day, 

 and barely enough fluid will be found in it to fill the pit two-thirds full; 

 but during the night, and until some time after sunrise in the morning, 

 great drops of the sweet fluid may be found hanging from its border. 

 This nectar is very attractive to certain insects, chiefly ants, wasps, and 

 mud-daubers. It is also sought at night by the moths of both Aletia 

 and HeUothte, the former of which had been seen to alternate sipping 

 this nectar with ovipositing. As I have elsewhere stated, the Iarva3 of 

 both these moths feed on the leaves of this plant, and both have been 

 attacked, removed from the plant, and killed before my eyes by ants or 

 wasps induced by tjris nectar to visit the leaves. 



On the lamina of the leaves of the bonnet squash a variable number of 

 pustule-like glands is found. These secrete an abundance of nectar, and 

 are constantly attended by ants of several species, which, from the dis- 

 tribution of the glands, are led to explore every inch of the leaf-surface. 

 I only found that the leaves of this plant were attacked by the larvae and 

 imagines of the large lady-bird, Epilaclma borealis, and as very few of 

 these were seen on them I could not determine their relations with the 

 ants. 



In Acacia sphcerocephala, the bull's-horn thorn, Mr. Belt tells us that 



The leaves are bipinnate. At the base of each pair of leaflets, on the mid-rib, is a 

 crater-formed gland, which, when the leaves are young, secretes a honey-like liquid. 

 Of this the ants are very fond, and they are constantly running about from one gland 

 to another to sip up the honey as it is secreted. But this is not all ; there is a still 

 more wonderful provision of solid food. At the end of each of the small divisions of 

 the compound leaflet there is, when the leaf first unfolds, a little yellow fruit-like 

 body united by a point at its base to the end of the pinnule. Examined through a 

 microscope, this little appendage looks like a golden pear. When the leaf first unfolds, 

 the little pears are not quite ripe, and the ants are continually employed going from 

 one to another examining them. When an ant finds one sufficiently advanced, it bites 

 the small point of attachment ; then, beiiding down the fruit-like body, it breaks it 

 off and bears it away in triumph to the nest. All the fruit-like bodies do not ripen at 

 once, but successively, so that the ants are kept about the young leaf for some time 

 after it unfolds. Thus the young leaf is always guarded by the ants, and no caterpil- 

 lar or larger animal could attempt to injure them without being attacked by the little 



* Glover, Agricultural Report, 1855, p. , points out the presence and secretion of 

 these glands. 



