298 ENTOMOLOGICAL NEWS. [December, 



tion of six. Here we may, perhaps, trace the existence of 

 an entomological fauna exceptionally rich in species, consider- 

 ing the area covered, to a geological foundation, as this canon 

 is unique in its construction among those of the western slope 

 of the Wasatches. This gives us not only variety of contour, 

 but also of soil composition and a corresponding flora with its 

 attendant insect proteges. 



Salt Lake City, situated at an elevation of 4,225 feet, repre- 

 sents practically the bottom point and the center of a radius of 

 about thirty-five miles, within which all the species herein 

 listed have been taken. The height at which the growth of 

 coniferous trees generally commences in northern Utah is in 

 the neighborhood of 6,000 feet, and an imaginary line drawn 

 at this altitude marks a decided change in both the flora and 

 the fauna above from that below, and while it is a notable fact 

 that similar situations in different localities do not always yield 

 the same species — each square mile being likely to have its own 

 peculiarities — many of the species seem to be restricted within 

 pretty well defined zones of altitudes, which I have endeavored 

 to indicate to the best of my knowledge in the list. 



It has been mentioned by visiting entomologists that they 

 have found collecting at light in Salt Lake City unprofitable, 

 and my own experience has often been decidedly the same. 

 During certain seasons, when good night collecting might be 

 fully expected, I have visited the electric lights after night 

 without finding anything of interest. Again, however, I have 

 taken a great variety of things at frequent intervals throughout 

 the summer and early autumn. In fact, I have found three 

 different butterflies {Pyrameis cardui, Pholisora catullus and 

 Pieris protodice) at light. Curiously, these three specimens 

 were found on different evenings under the same light, and no 

 other diurnals ever noted under any but that one individual 

 lamp. I believe it has often been noted by nocturnal collectors 

 that certain lamps seem to have special power of attraction for 

 insects, and in endeavoring to account for the fact, I have 

 observed that those lamps which are near the outer limits of 

 brightly illuminated districts, and in more or less sheltered 

 situations seem to be the particular ignes fatui of insect kind. 



