METAZOA INSECTA. 459 



fact, should hardly be called by the name, since they are 

 mere swellings. 



The more specialized Frenatae may be divided into two 

 groups : one represented by the Orneodidae, Pyralidae, 

 Tortricidae, Tineidae, and Sesiidae, and the other by the 

 so called frenulum conservors and the frenulum losers. 



The larvae of the plume moths or Orneodidae spin no 

 cocoon but they often fasten themselves within a curved 

 leaf, thereby showing a tendency towards cocoon making. 

 The adults (No. 1164, Orneodes hexadactyla Linn.) of 

 some species have each of the four wings divided into 

 six parts, giving a feathery appearance to these organs of 

 flight. 



The Pyralidae are especially interesting since certain 

 larvae of this family have become adapted for aquatic life. 

 Tufts of respiratory filaments or gills which are supplied 

 with special air-tubes occur on each side of the body (PI. 

 1165, fig. i, Paraponyx obscuralis Gr. ; fig. 2, respiratory 

 filament). The air contained in the water passes through 

 the walls of the filament and supplies the tubes. These 

 caterpillars, according to Hart, 1 are usually concealed by 

 leaves which the insect has fastened together with silk ; 

 when these hiding places are broken up, the caterpillars 

 swim about in the water. The larva spins a dense cocoon. 

 The pupa (fig. 3) is without gills, but has conspicuous 

 spiracles on either side. According to Miall * the cocoon 

 of Paraponyx stratiotata though immersed in water, is 

 filled with air, and the facts tend to prove that the spir- 

 acles of the pupa are used in respiration. 



The larvae of the Tortricidae have the habit of rolling 

 up leaves which serve both for a habitation and for food. 

 Here they live together in companies. When ready to 

 transform the pupae cling to the surface of the nest, while 

 the winged insects fly away leaving the empty pupa skins 

 as seen in No. 1 166. 



1 Bull. 111. State Lab. Nat. Hist., IV, 1895, p. 167. 



2 Nat. Hist. Aquatic Insects, 1895, p. 233. 



