xii INTRODUCTION. 



figures also of such known species as were met with 

 in the course of my expedition. 



Three species are figured here which do not, so far 

 as I am aware, occur in California or Oregon. Of 

 these, two Lioptilus paleaceus, Zell., and Oxyptilus 

 periscelidactylus, Fitch are given for convenience of 

 comparison with some of their near allies ; the other, 

 Platyptilus petrodactylus, Walk., to enable those who 

 have not access to Mr. Walker's types to become 

 acquainted, through this pamphlet, with all the 

 three North-American Pterophoridse which he has 

 described. 



The arrangement followed here is that of Herr 

 Pastor Wallengren, as explained in his ' Skandi- 

 naviens Fjadermott,' published in 1859 (K. Vetensk.- 

 Akad. Handlingar, B. iii.), of which Prof. Zeller has 

 given an abs tract in the ' Stettiner ent. Zeitung ' for 

 1867, and of which the Latin diagnoses have been 

 translated by Dr. R. C. E. Jordan in a very useful 

 paper in the ' Entomologist's Monthly Magazine,' 

 nos. 65, 66, 67, for the months of October, November, 

 and December of the year 1869. 



