METAZOA INSECTA. 455 



be called worms, our classification would be most errone- 

 ous. When it is borne in mind that the caterpillar is a 

 specialized animal, as compared with the worm, having 

 well developed mouth parts, jointed legs, adaptive prop- 

 legs, and embryo wings, it becomes evident that the reten- 

 tion of "worm " as descriptive of young Lepidoptera leads 

 only to a confusion of ideas which is always to be 

 avoided. 



The moths constitute the more primitive group cf the 

 Lepidoptera or scaly-winged insects, while the butterflies 

 are more specialized. This arrangement, based on struc- 

 ture and development, is in harmony with the palaeonto- 

 logical record of the order. 



Jugatae. Eriocephala calthdla possesses characters 

 allying it with the Neuroptera, Mecoptera, and Trichop- 

 tera. The caterpillar (PI. 1154,) is provided with eight 

 pairs of abdominal prop-legs, each ending in a curved 

 spine and resembling the similar prop-legs of the Panorpa 

 larva. It is specialized by addition in possessing rows 

 of odd ball-like appendages. The adult has the collar- 

 like prothorax, while the mesothorax and metathorax are 

 long and slightly consolidated. These two thoracic seg- 

 ments are of nearly equal size, like the two pairs of wings 

 which they bear. These wings are similar in their vena- 

 tion and are fastened together by a membranous lobe, the 

 jugum (see PI. 1157, fig. i,/), extending from the pos- 

 terior basal part of the fore wing ; in this way these moths 

 resemble the Trichoptera. 



The wings are covered with scales or modified hairs, 

 the common character of the order, and in addition to 

 these scales there is a covering of fine hairs, which, 

 according to Kellogg 1 are found in the Jugatae but not 

 in the more specialized Frenatae. A similar coating of 

 hairs is found in the Trichoptera, which indicates that it 



1 Kansas Univ. Quarterly, III, no. I, 1894, p. 80; also Amer. 

 Nat., XXIX, 1895, p. 250. 



