I90 INTRODUCTION 



so forth, not only sucking nectar, but — being dusted with pollen below — serving also as 

 active pollinators. No structural adaptations to flower-food have, however, been seen, 

 unless the small size of Anthocoris can be so regarded. The elongated proboscis, 

 fitted for sucking nectar from tubular flowers, is just as characteristic of the other — 

 and more numerous — land-bugs which never visit flowers, and it cannot therefore 

 be regarded as an anthophilous adaptation. No flower has been observed as 

 specially adapted to pollination by bugs, though such might be a quite conceivable 

 possibility. Nor is a single species of flower known for the pollination of which 

 bugs are of special importance, and accordingly the structure of their proboscis need 

 not be considered. 



Among the Neuroptera (net-winged insects), Panorpa communis has now and 

 then been observed visiting flowers and sucking nectar. According to Muller 

 (' Fertilisation,' p. 31) it is easy to satisfy oneself that it is really anthophilous, for it 

 visits some flowers in which the nectar is somewhat deeply seated (e. g. Polygonum 

 Bistorta, Eupatorium cannabinum, and so forth), plunging its long beak-shaped head 

 into the various nectar receptacles. One might even be inclined to look upon the 

 snout-like prolongation of the head as an adaptation to getting nectar from these flowers, 

 were it not that the nearly related little wingless Boreus hiemalis, which never visits 

 flowers, but lives in moss, possesses the same character, which may therefore be of 

 diflferent origin. Species of Hemerobius, Sialis, Ascalaphus, Perla, and others, are 

 frequently met with upon the flowers of Umbelliferae. They bend their heads down 

 to the fleshy disk-like nectaries and doubtless lick up their secretion. Small dragon- 

 flies (Agrion) sometimes settle on flowers (Spiraea), but apparently only to sun 

 themselves. 



Among Orthoptera only the earwig (Forficula auricularia and other species) 

 has to be considered as a visitor of flowers (Papaver, Tropaeolum, TroUius, Cam- 

 panula, Compositae, roses, pinks, peonies, and so forth), into which it creeps during 

 the day, and feeds upon the softer parts at night. 



Grasshoppers spring and fly about in quest of food on to various parts of plants, 

 including the flowers. 



Our indigenous Orthoptera do not show any anthophilous adaptations. But 

 Darwin states that several New Zealand grasshoppers were observed by Mr. Swale 

 to polhnate papilionaceous flowers (Ann. Mag. Nat. Hist., London, ser. 3, ii, 1858, 

 p. 461), but Hermann Muller remarks ('Fertilisation,' p. 30, note) that this seems 

 very questionable and scarcely credible. 



In South Brazil Fritz Muller observed a cockroach very similar to Pseudomops 

 laticomis Perty to be a diligent visitor of flowers, occurring frequently, e.g. on the 

 garden composite Polymnia edulis, apparently to feed on the nectar. 



F. Stages of Adaptation in Insects which visit Flowers. 



Though members of all insect orders visit our indigenous flowers, there are 

 very great difi'erences between these orders in respect of the number of anthophilous 

 species and individuals, and also as to the degree of anthophily. Their importance 

 for pollination of flowers and the amount of correlated adaptation are therefore very 

 far from being the same. 



