AXTENX.T? OK LKITDOPTKKA. 41 



dorsal aspect, and it bears on its ventral aspect wide expansions, 

 considerably compressed. These have hairs of the third type ar- 

 ranged on their sides in a semicircle with its opening directed ven- 

 trad. Within the semicircle is an abundance of pits and rods. The 

 ventral expansions are as long as the segments which bear them, 

 and n(>ar the apex of the clavola, where the shaft is smaller in (U.ini- 

 eter, they cause it to be more or less recnirved, as we find it among 

 the Hosperiina. In some of the pectinate forms, e. g., Snieruithus 

 (jeiiiiiKititx, the ventral expansions are well developed and extend far 

 ventrad of the bases of the {)eetinations. Such forms are found 

 among those members of the groiq) which are not so swift in flight 

 as the other Sphingidje. 



The evidence of the antennte in all these cases just noted is 

 neither clear enough nor strong enough in itself to warrant any 

 change in the classification, but it may suggest the direction of work 

 on other organs. For the relationships of the larger groups, I do 

 not believe the antenuje furnish as good guides as do other organs. 

 For, while they are subject to great variation by reason of the pe- 

 culiar habits and environment of the particular genus or species, 

 the}' do not afford a sufficiently large basis for variation to leave 

 a stable and constant ground-work for the tracing out of the paths 

 by which the specializations are brought about. In smaller groups 

 they are of great value. The best example of this is perhaps to be 

 seen among the Saturniina in the Fi-enulum-losers. They are often 

 of value also when other organs seem to be constant in a number of 

 forms, e. r/., in the Xoctuidae, Agaristidre, Pericopidae and Lyman- 

 triidie, the wing structures are pretty constant, but the antennal 

 structures show considerable variation and afford characters to dis- 

 tinguish the groups. 



The FRENULtrM-LOSERS. 



The FiTiiulum-losers include the Saturniina, Lacosoniid;e, Lasio- 

 campidse anumg the moths, and the superfamilies Hesperiina and 

 Papilionina comprising the skijjpers and butterflies. The following 

 table will serve to separate the anteniue of the males of this group. 



THE FRENULUM-LOSERS. 



A. Antenna pectinate. 

 B. Pectinations ventral. 

 C. Pectinations of at least the cephalic side not extending to the apex of the 



clavola SATURNIINA. 



CC. Pectinations extending to the a])ex. 



TRANS. AM. ENT. SOC. XXIII. (6) MARCH, 1896. 



