Vol. XI] COLE AND LOVETT—LIST OF OREGON D1PTERA 225 



FAMILY BIBIONID^E 



Fig. 9. Bibio nervosus Loew 



The males and females of these ungainly little "March 

 flies" often differ considerably, the females having grotesque 

 little heads. They emerge in April and May and often on 

 bright sunshiny days they will appear in swarms, sailing 

 about in an aimless sort of way. 



The larvae have a false segment behind the head which is 

 well developed and has spiny processes. They are scaven- 

 gers, feeding on decaying vegetable matter or excrement. A 

 few feed on grass roots. 



141. Bibio hirtus Loew 



This species is usually less common that the following and 

 emerges a week or more later. It has been reported as in- 

 jurious to turnips in one section of the state. 



142. Bibio nervosus Loew 

 Very common in spring and early summer. 



143. Bibio variabilis Loew 

 Reported from Oregon by Coquillett. 



