ANTENNiE OF LEPIDOPTERA. 23 



The long, stout, rigid hair of the second type arose very early, 

 before the separation of the Jugatre from the Frenatie, and long 

 before the third type originated. The latter type was developed 

 subsequent to another division which took place after the separation 

 of the Jugatue from the Frenatai, and also after the Hesperiina and 

 Papilionina had branched off from the Frenate stem. It departs 

 less widely from the first type, and it is evidently specialized as a 

 touch organ. It reaches its highest development among the Noc- 

 tui(l:e, Lymantriidie and Arctiidic. 



At first siglit the pits are very different from the simple sense-hair. 

 Nevertheless, I believe that in essential characters they differ from 

 them much less than do the hairs of the second type. The antenuie 

 of a female Eparyyrem titijru.i will show that iu many of the pits 

 hairs very like those of the first type occupy the place of the short 

 rods found in the more highly developed pits, and different specimens 

 will present various stages of transition from the hair in a compara- 

 tively slight pit to a short rod in a deeper one. This shoAVs that the 

 structure is not yet definitely fixed in character, and that it may vary 

 greatly in a short time. 



The cones are a distinct development, however, and in all prob- 

 ability originated but once. This must have been after the separa- 

 tion of the Jugatse and the Frenati3e, and also after the Hesperiina 

 and Papilionina had l)ranclied off from the latter. All the Frenatie, 

 except these two superfamilies and possibly the Pyromorphidio, pos- 

 sess these organs. They are quite constant in location. In all of 

 the ]Microfrenatpe, and in most of the Macrofrenatre, they are dis- 

 tributed one to a segment as shown in Figs. 46 -50, and they form a 

 very conspicuous feature of the antenna. In some of the Macrofre- 

 natie, however, they number more than one to a segment, and in 

 pectinate antennte they have often migrated from the shaft to a posi- 

 tion ui)on tlie i)ectinations. Fig. 25 represents a portion of the ven- 

 tral aspect of the antenna of Phryga)udea calif ornica where the 

 cones still occcupy a position on tlie shaft. Fig. 27, representing a 

 portion of the right antenna of a male Zeuzera pyriui, shows this 

 migration with the cones situated part way toward the distal ends of 

 the pectinations. Fig. 30 shows a portion of a pectination of the 

 antenna of a male Xotolophus lencodujma with the cone at the ex- 

 treme distal end. Among the Saturnidic, the number of cones to a 

 segment is greatly increased. Fig. 7 represents a distal portion of 

 the antenna of a female Trojxva /una with clusters of cones in the 



TKANS. AM. KNT. SOC. XXIII. JANUARY. 1896 



