368 INSECTS INJURIOUS TO VEGETATION. 



renheit's thermometer, continued during twelve hours, will kill 

 the insects in all their forms. Indeed the heat may be reduced 

 to one hundred and four degrees, with the same effect, but the 

 grain must then be exposed to it for the space of two days. The 

 other means, that have been employed for the preservation of 

 grain from these destructive moths, it is unnecessary to describe ; 

 they are probably well known to most of out farmers and millers, 

 and are rarely so effectual as the process above mentioned. 



7. Feather-winged Moths. Alucitm. i 



The last tribe of Lepidopterou^ insects, remaining to be no- 

 ticed, contains the Alucit^ of Linnaeus, or feather-winged 

 moths, called PTEROPHORiDiE by the French naturalists. These 

 moths are easily known by their wings being divided lengthwise 

 into narrow, fringed branches, resembling feathers. The fore- 

 wings in the genus Pterophorus are split, nearly half way, into 

 two, and the hind-wings are divided, to the shoulder-joint, into 

 three feathers; and each of the v^^ings, in Alucita, consists of six 

 feathers, connected only at the joint. The antennas of these 

 moths are slender and tapering ; the tongue is long ; the feelers 

 are two in number, and of moderate length ; and the body and 

 legs are very long and slender. When at rest their wings do not 

 cover the body, but stand out from it on each side, not spread 

 however, but folded together like a fan, so that only the outer 

 part of each of the fore-wings is visible. They fly slowly and 

 feebly, some of them by day, and others only at night, and, when 

 on the wing, they somewhat resemble the long-legged gnats. 

 Their caterpillars are rather short and thick, are clothed with a 

 few hairs, and have sixteen short legs. Most of them live on the 

 leaves of low or herbaceous plants, and, when about to change to 

 chrysalids, they fasten themselves by the hind-feet and by a loop 

 over the back, like the Lycaenians. Those which belong to the 

 genus Alucita are said to live in buds, and undergo their transfor- 

 mations in thin, transparent cocoons. The number of species in 

 this tribe is small ; and those that are found in this country are so 

 few, and of so little consequence, in an economical point of view, 

 that a particular description of tlrem will not be necessary in this 

 treatise. 



