FOOD OF FUNGI 99 



in length. But the fungus may infect perfect insects 

 as well as caterpillars; moths and butterflies, beetles, 

 wasps, bees and spiders are attacked, and the death- 

 rate due to the activity of these Fungi among insects is 

 enormous. 



All Fungi are destitute of chlorophyll, hence they 

 are unable to elaborate carbon-compounds from the 

 carbon dioxide of the atmosphere. Such carbonaceous 

 food as they require must be obtained from organic 

 material. Thus Fungi are either saprophytic or para- 

 sitic; in the former case they obtain food from the 

 dead bodies, or waste, of animals and plants, while 

 in the latter they prey upon living plants or animals. 

 It is among the parasitic Fungi that we have so many 

 pests, some of which inflict serious financial loss upon 

 man. The saprophytes serve a most important use 

 in that they attack useless organic remains, cause them 

 to decay and form a highly nutritive humus soil in 

 which higher plants may nourish. In this use the 

 Fungi are assisted by the saprophytic Bacteria. Fungi 

 resemble animals in that they consume ready-made 

 organic food, absorb oxygen, and give off carbon 

 dioxide. Such being their habit, they cannot be re- 

 garded as primitive plants. It is probably right to 

 assume that they have descended from green Algae 

 which lost chlorophyll owing to parasitic or saprophytic 

 practices. But while all Fungi are marked by the 

 absence of chlorophyll, we must not conclude that all 

 plants destitute of this pigment are Fungi. There is 

 quite a number of flowering plants, among which 

 Toothwort and Dodder are familiar examples, that 



