28 NORTH AMERICAN DIPTERA 



Superfamily Tipuloidea 



These are the "Crane Flies" and include the families Tanyderidae, 

 Ptychopteridaj, Trichoeerid«, Tipulidie and Anisopodidie. The first four 

 mentioned families are characterized bv the presence of a V-shaped 

 suture on the mesonotum, and have, until recent years constituted the 

 family Tipulidte. In the Ptychopteridai this suture is more or less 

 obsolete posteriorly where it extends into the prescutellar depression 

 but its form is always very well marked. The inclusion of the Anisopo- 

 didas with the Crane-Flies may be questioned by some students of the 

 Order. I think the question is a debatable one : at any rate, the family 

 seems to form more or less of a connecting link between the Tipulids 

 and Mycetophilids. 



The manuscript for the Tipuloidea has been prepared by Dr. C. P. 

 Alexander and this fact assures the student of thorough and accurate 

 keys together with the latest views on generic limits and classification. 

 The study of this group might almost be said to be a ''world apart" in 

 the study of Diptera and I cannot fully express my gratitude to Dr. 

 Alexander for the service he has rendered in preparing this jJ^irt of 

 the work. 



