257] NOCTUID LARVAE— RIPLEY 15 



condition is widely distributed throughout the family. A peculiar retic- 

 ulate fuscous marking is frequently found on the vertex, where it usually 

 stands out prominently against the light brown background. 



In 1896 Dyar introduced the first system for designating the setae of 

 the lepidopterous larval head. He numbered those of each sclerite with 

 Roman numerals from dorsal to ventral margin, departing from this scheme 

 slightly on the ventral portion of the vertex. jMore recently Dampf has 

 emphasized the taxonomic importance of the head setae in the Psychidae 

 and their allies. He divided the head-setae into groups on the basis of 

 the tendency exhibited to vary their position in the larvae of different 

 species by groups rather than individually. This interpretation led him 

 to refer to them according to these groups. In his study of microlepidop- 

 terous larvae Heinrich followed the system of Dampf, which he supple- 

 mented by numbering the setae, pointing out the fact that these group 

 migrations are due to the contracting or expanding of the parts of the 

 head-capsule. Fracker and Forbes designated the setae of the head by 

 the Roman numerals of Dyar. Forbes also numbered the labral setae. 



In devising a system which may be applicable to the study of the homol- 

 ogies of larval setae throughout the order, and very possibly throughout 

 the larvae of dififerent orders, it seems preferable to name them after the 

 sclerites on which they occur rather than according to certain groupings 

 which are not well understood, except perhaps in the few families studied 

 by Dampf and Heinrich. The latter author disagrees with the former as to 

 the group in which a certain seta should be included. It seems likely that 

 in various families in which the trend of specialization has been divergent 

 this grouping relation may be altogether different. We find in the Noctui- 

 dae, for example, certain setae within one of Dampf's groups exhibiting 

 wide variation in position with reference to each other. The system of 

 Dyar and Forbes, with minor changes, has, therefore, been followed in 

 this paper. 



These setae may be conveniently designated by the abbreviation for 

 the sclerite bearing them followed by an Arabic numeral. Thus VI refers 

 to the seta typically located furthest dorsad on the epicranium. The ab- 

 breviations, 0, V, a, /, c, and I stand respectively for occiput, vertex, ad- 

 frontal, front, clypeus and labrum. A few minute setae hitherto disre- 

 garded, although of general occurrence, have been named. This same 

 system of naming has been applied to the ocellarae, oc being the abbrevi- 

 ation used. 



MOVABLE PARTS OF THE HEAD 



The antennae of lepidopterous larvae appear to be generally uniform 

 in structure and primary setal armature. That of Cirphis unipuncta (Figs. 

 19-21) may be regarded as typical for the order. The antennaria bears a 



