The Moths and Butterflies 



371 



by collectors and nature students. But these moths are of particular impor- 

 tance and interest to entomologists because they are undoubtedly the oldest 

 or most generalized of living Lepidoptera ; they represent most nearly, among 

 present-day existing moths, the ancestral moth type. This is shown most 

 conspicuously by the similarity in size, shape, and venation of the fore and 

 hind wings, for the primitive winged insects had their two pairs of wings 

 equal, while nowadays the various orders show a marked tendency to 

 throw the flight function on one pair, either the fore wings, as among the 

 flies (Diptera), wasps, bees, etc. (Hymenoptera) , and Lepidoptera, or the 

 hind wings, as with the locusts, crickets, etc. (Orthoptera), and beetles (Cole- 

 optera), the other pair becoming much 

 reduced in size, or even, as in the 

 Diptera, wholly lost. Quite as impor- 

 tant, if not more, although not so con- 

 spicuous, as an evidence of the ancient 

 character of the jugate moths, is the 

 condition of the mouth-parts, certain 

 species in the group having true biting 

 mouth-parts, with well developed man- 

 dibles, short lobe-like maxillae, and short, 

 truly lip-like labium. All other moths 

 and butterflies have the mouth-parts 

 specialized for sucking, with the man- 

 dibles rudimentary or wanting, the max- 

 illae produced and apposed to form the 

 long flexible sucking-tube, and the under 

 lip (labium) reduced to a mere immovable 

 functionless sclerite. The presence of 

 the jugum for tying the fore and hind 

 wings together, as in the caddis-flies, FIG. 524. Diagram showing venation 

 undoubtedly nearly allied to the moth of wings in monarch butterfly, ^n<ma 

 J plextppus. c., costal vein; sc., sub- 



ancestors, instead of the specialized costal vein; r., radial vein; cu., cubi- 



frenulum as in other moths, is also evi- 

 dence of the ancestral type displayed by 

 the Jugatae. 



The Micropterygidae, represented in 

 this country by two genera, Eriocephala, 

 with four species, and Epimartyria (Micropteryx), with two species, are among 

 the smallest moths we have, the largest not expanding more than one-third 

 of an inch and the smallest only one-fifth of an inch, the body being about 

 one-tenth of an inch long. They are indeed almost invisible when flying, 

 and are only very rarely taken by collectors. They fly in the sunshine, 



tal vein; a., anal veins. The base of 

 the medial vein (lying between radius 

 and cubitus) is obsolete, but its 

 branches still persist, lying between 

 branches of radius and cubitus. 

 (Natural size.) 



