HYMENOPTERABEES 147 



In the species of the above-named three genera, the habit exists of wetting 

 the pollen with honey before heaping it up in the collecting-apparatus, thus making 

 it into a coherent mass, which does not need to be entirely enclosed by collecting- 

 hairs. This mass can easily be taken out of the collecting-apparatus and at once 

 used as larval food. The pollen-apparatus of the hind-legs is therefore extremely 

 perfect and permits considerable economy of collecting-hairs, and also much saving 

 of time in emptying the collecting-apparatus and preparing the larval food. In the 

 genera Eucera, Anthophora, Dasypoda, and Panurgus, the collecting-hairs are limited 

 as in the previous genera to the tibiae and basal joints of the tarsus, so that here too 

 a rapid and convenient removal of the collected pollen is possible. Indeed Eucera 

 and Anthophora already possess an arrangement resembling the collecting-apparatus 

 of Bombus, for a greater broadening of the pollen-receiving tibia and basal tarsal 

 joint has rendered possible a relatively small development of hairs, which interfere 

 with flying and creeping movements. In Panurgus, the hairs on the tibia and 

 proximal tarsal joint, which represent the collecting-apparatus, are considerably longer 

 and therefore more in the way than in Eucera and Anthophora, but even here they 

 are entirely confined to these regions. In Dasypoda, on the other hand, not only are 

 the collecting-hairs of the tibia extraordinarily long, so that the movements of these 

 bees are slow and almost clumsy compared with those belonging to the genera already 

 mentioned, but the thigh, the trochanter, and coxa are also beset with long, thick 

 hairs, so that these parts share in the collecting of pollen, though in a lesser degree. 

 Dasypoda hirtipes has such long feathery collecting-hairs on the coxae, tibiae, and 

 the greatly elongated basal tarsal joints of the hind-legs, that it is able to heap upon 

 them immense balls of pollen, which may be half the size of the abdomen. Sprengel 

 ('Entd. Geh.,' p. 370) observed this bee on Hypochoeris radicata. 'At noon, 

 during beautiful weather, I noticed a bee on this plant, with such large balls of pollen 

 on its hind-legs that I was amazed. They were not much smaller than the entire body 

 of the insect, and gave it the appearance of a heavily-laden pack-horse. Yet the bee 

 could fly with its burden at a great rate, and was not yet contented with the provision 

 it had collected, but flew from one flower-head to another to increase its load.' 



Hermann Miiller (Verb, nathist. Ver., Bonn, xli, 1868, pp. 1-62) states that a single 

 load of pollen, such as a female of Dasypoda hirtipes carries to her nest, weighs 

 about half as much as her own body. Five or six such loads, after they have been 

 moistened with honey, are made by the bee into a ball weighing o-23-o-36gr., and 

 this is entirely consumed by the larva that develops upon it. 



The species of Panurgus with their highly developed collecting-apparatus visit, 

 almost exclusively, yellow Composites of the group Cichoraceae, chiefly limiting their 

 activity to the collection of pollen. When on a capitulum they often turn over on 

 their sides or roll about, and are almost hidden among the florets. 



As regards specialization in relation to flowers these four genera are consider- 

 ably lower in the scale than Apis, Bombus, and Macropis, for they are not in the habit 

 of moistening the pollen before loading themselves with it, so as to form a coherent 

 mass which can be taken from the collecting-apparatus in the shortest possible time 

 (of. p. 146). 



The genera Anthrena, Halictus, and Prosopis are at a much lower stage in 

 respect of adaptation to flower-food. In many species of the two first-named genera 



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