Moths 229 



dusky band. This insect flies by day, and is exceedingly abundant 

 in Colorado in late summer. Although it is a native of the State, 

 it is probable that most of the moths seen late in the season come 

 from the south. The larva not only injures cotton, but is very 

 fond of the ears of sweet corn, and of tomatoes. 



The Lasiocampidae are represented by Malacosoma fragilis, 

 the velvety larvae of which make web-like structures in trees, and 

 are often very destructive, especially in groves of aspens. They 

 are known as Tent-caterpillars. 



The large group of Geometridae (the word meaning earth- 

 measurers) consists of mostly broad-winged slender bodied moths, 

 the larvae of which are loopers. A monograph of these insects, 

 by A. S. Packard, was published in 1876 as one of the reports of 

 Hayden's Survey of the Territories. We cannot discuss the 

 various species here, but it is worth while to mention the Ennomos 

 ochreatus of Hulst, which appears in the fall, and looks just like 

 the yellow fallen leaves among which it may frequently be found. 

 One of our most beautiful and striking species is Mekmaea 

 magdalena of Hulst, which I found at Grand Lake in September. 

 It seems to be excessively rare. 



The Pyralidae are moths of medium or small size, and slender 

 build. The species of Loxostege are known as web- worms in the 

 larva state, and are often very destructive. The sugar-beet 

 Web-worm (Loxostege sticticalis) is well described by Asa C. 

 Maxson,* who says: "The sugar-beet webworm is one of the 

 most destructive leaf-eating insects attacking the sugar-beet. 

 Like many of our most injurious insect pests, it was introduced 

 into this country from the Eastern Hemisphere, appearing first 

 on the Pacific coast." Some authors believe, however, that it 

 was native in the west, having spread by natural means from 

 Asia. Mr. Maxson states that in 1915 this insect caused a loss of 

 not less than 26,450 tons of beets. Over 16,000 acres were 

 sprayed with Paris green, 84,000 pounds of this substance being 

 used. But for this, the loss would have been very much greater. 



There are many families of small moths, some of them of 

 unusual interest. The beautiful white Tegeticula alba (or T. 

 yuccasella) is the means of fertilizing the Yucca plant. The 



♦Principal Insect Enemies of the Sugar Beet (1920); a very valuable book issued by the 

 Great Western Sugar Company. 



