66 OTHER 'MYRIAPODS' 



the soil to feed without hesitation at any hour of the day. It is not 

 uncommon to find them lying perfectly motionless on the surface 

 of the ground where they are fully exposed to the sunlight. When 

 in motion the antennae are kept constantly moving, but while 

 feeding they are, as a rule, held backwards. Symphyla can run 

 very rapidly when disturbed and quickly retreat into the soil. If 

 their antennae are touched with a camel's hair brush or other 

 instrument they reverse their course with lightning speed. In 

 turning round the posterior end of the body is held still and acts 

 as a pivot (Verhoeff, 1934). The very young, however, never come 

 to the surface of the soil and apparently do not feed until they have 

 moulted a second time. Symphyla are not restricted to any par- 

 ticular level of the soil, and may be found from the surface to a 

 depth of four feet or more. Moisture is the most important factor 

 determining their vertical distribution, but temperature, soil tex- 

 ture, structure and vegetation also influence them. 



Symphyla appear to be vegetarians and to prefer decaying and 

 succulent materials although they will feed on many kinds of 

 lower plant life. Newport in 1845 thought that they must be car- 

 nivorous, preying perhaps on the microscopic Poduridae to be 

 found in the same places, but Duboscq, some years later, noted the 

 absence of a poison gland in Scolopendrella. Scutigerella immaculata 

 normally feeds upon decaying vegetable matter but may attack 

 living plants, often doing very much damage to field and glass- 

 house crops such as young seedlings, asparagus, lima beans, peas, 

 tomatoes and cultivated flowers. It has conical taste sensillae at the 

 apex of the second maxillae (considered to be homologous with 

 the gnathochilarium of Diplopoda), but these are simpler in struc- 

 ture and considerably fewer in number than those of millipedes. 

 Population studies in the field and greenhouses show that Sym- 

 phyla may be present in large numbers, sometimes as many as 22 

 million per acre out of doors, and 90 million per acre in glass- 

 houses. Suitable methods for checking damage in greenhouses 

 consist of using raised benches, steam treatment, insecticides and 

 soil fumigation (Michelbacher, 1938). 



As in the case of the Pauropoda, little is known of the predators 

 of these creatures, but Chilopods are said to be among the most 

 important of their natural enemies. A large Gamasid mite has been 



