FLOWERS AND THEIR WORK. 



241 



Dog Rose, Rock Rose, St. John's Wort, etc. Some flowers 

 show remarkable adaptations for pollination by flies, which 

 are, as a rule, much lower in intelligence 

 than the other classes of flower-visiting 

 insects. 



One of the commonest beetles seen visiting 



flowers is a small bronze- black one called Meli- 



gethes, but very few beetles have tongues over 



3 mm. Most of the larger and longer-tongued 



flies (e.g. the Tabanids Gad-flies, "Cleggs," 



Horse-flies) do not visit flowers, those just men- 

 tioned being blood-suckers, but some (with tongues 



sometimes as long as 12 mm.) are regular flower- 

 visitors. These belong chiefly to two families 



Hover-flies (Syrphids) and Bee-flies (Bombylids). 



The former (Eristalis, Syrphis, Rhinyia, etc.) often 



resemble bees and wasps in having a banded body, 



and many flowers are adapted for their visits, 



e.g. Speedwell, in which the two stamens form an 



alighting-place for the fly. The Bombylids also 

 visit flowers, and some are nearly as clever as the 

 bees they resemble at finding concealed honey 

 with their long tongues ; of the few British forms, 

 Bomtylius (hairy body, humped thorax, slender 

 legs) is of great importance in the pollination of 

 spring flowers, e.g. Primrose (see Art. 379). 



Among the smaller flies (tongues less than 3 mm. 

 long) several visit flowers, e.g. Lucilia (small blue- 

 bottle), Anthomyia, Dung-flies, Midges, Thrips ; 

 some of these feed on decaying matter, and some 

 flowers appear to be specially adapted for their 

 visits, having a peculiar odour, e.g. Arum, Haw- 

 thorn, Moschatel, Rowan. 



Examine the peculiar "flowers" of the Cuckoo- 

 pint (Arum), so common in our hedgerows, where 

 it blooms in April and May (Fig. 88). The whole 

 "flower" is enclosed in a large green and purple 

 leaf (the spathe). The upper portion of the spathe 

 opens, exposing the brightpurple club-shaped upper 

 part of the spadix, while the lower bulbous portion 

 remains closed except at the top, where it eon- 

 tracts to form a narrow throat. Cut open the 

 lower part, and you see that the spadix is con- 

 tinued downwards, forming an axis, round which 



are situated two clusters of small flowers. The upper cluster is a 

 dense mass of male flowers, each consisting of a single stamen ; and 

 the lower is a similar mass of female flowers, each consisting of a 

 single carpel. Above each cluster are some abortive flowers that are 



S.B. 16 



Fig. 88. Spadix of 

 Arum. 



Spathe removed to 

 show the Flowers. 



