LEPIDOPTERA 207 



Family Yponomeutid.-e 



This is not a large family but it contains several species of economic 

 importance among which is the cedar tineid, Argyresthia thuiella, the 

 larvae of which feed on the leaves of cedar, the apple-fruit miner Argy- 

 resthia conjugella, the larvae of which burrow in all directions in the fruit 

 causing it to decay, the ermine moths and the ailanthus webworm. 



The ailanthus webworm, Atteva punctella. — The larvae live in communi- 

 ties in a slight silken web on the Ailanthus; they feed on the leaves 

 and also gnaw the leaf-stalks in two. When the larva is full-grown it 

 suspends itself in the middle of a loose web and transforms there. The 

 adults appear in September and October and pass the winter in this state. 

 The adult is very striking in appearance. The fore wings are bright 

 marigold-yellow with four bands of round pale sulphur-yellow spots upon 

 a brilliant steel-blue ground. The hind wings are transparent, with a 

 dusky margin and blackish veins. The wing-expanse is about 1 inch. 



The ermine-moths, Yponomeuta. — There are several species of the 

 typical genus of this family that have received the common name ermine- 

 moths, because of the color of their fore wings, which are snowy white 

 dotted with black. One of these, Yponomeuta padella, is an introduced 

 species which is an apple and cherry pest. The larvae live in a common 

 web, and in this they spin their cocoons. 



The name ermine-moths is applied also, especially in England, to 

 some of the Arctiidae that are white spotted with black. 



Family AZgerudje 



The Clear-winged Moths 



The clear-winged moths constitute a very remarkable family, many 

 of them resembling bees or wasps in appearance more than they do 

 ordinary moths, a resemblance due to their clear wings and in some cases 

 to their bright colors (Fig. 357). There are a few moths 

 in other families, that have a greater or less part of the 

 wings devoid of scales; but they are exceptions. Here 

 it is the rule that the greater part of one or both pairs 

 of wings are free from scales. In a small number of 

 members of this family the wings are scaled throughout 



■ Fig ^^7 



and the wings are held together by hamuli. 



These insects are of moderate size; as a rule they have spindle- 

 shaped antennae, which are terminated by a small silky tuft; sometimes 

 the antennae are pectinate; the margins of the wings and the veins of 

 even the clear- winged species are clothed with scales; and at the end of 

 the abdomen there is a fan-like tuft of scales. 



The fore wings are remarkable for their extreme narrowness and the 

 great reduction of the anal area (Fig. 358); while the hind wings have a 

 widely expanded anal area. The number of anal veins in the hind wings 

 varies greatly within the family, the number ranging from two to four. 



Another remarkable feature of the wings of these insects is that in the 

 female the bristles composing the frenulum are consolidated as in the 

 male; this condition exists in the females of a few members of other 

 families. The females of the ^geriidae possess a frenulum hook; but this 

 is not so highly specialized as that of the male. 



