80 JOHN B. SMITH. 



parisons. The affinity of these forms witli pellucid wings to the St'sudae 

 is marked by the internal vein of the primaries being very close to the 

 margin (in Sesia it is absent) and by the absence of the costal vein of 

 secondaries. In this genus the " independent" vein is feebly indicated in 

 the secondaries, and they are thus 7 veined. 



The family should follow the Scsndae, forming through the genera 

 Lycomorpha and Anatolmis the connection with the Pyroniorphidae on 

 the one hand, and the Ctennchidae on the other. 



The antennal structure in these genera agrees essentially with that of 

 the Pyromorptliidae, and they are very similarly placed. 



Ctenucha and Scepsis agree essentially in structure. The secondaries 

 lack the costal vein, but have two free, or internal veins, thus differing 

 at once from the Syntomoidae. The venation of primaries takes a 

 decided Bombycid or even Noctmd character, and the affinities to the 

 Arctiidae are strongly marked. The larva sustains this view, and forms 

 a strong argument against a union of Ctenucha with the Zygaemdae. 

 A reference to the figures of Plate III will enable the student to make 

 his own comparisons. 



While I do not think tlie head structure entitled to nearly as much 

 weight as Dr. Packard gives it, yet in all the genera hereinbefore dis- 

 cussed there is one element of head structure entitled to great weight, 

 and that is the position of the antennas. In the Xoctm'dae they are 

 inserted close to the compound eyes and as far apart as the width of the 

 head will allow. In the Zygaenidac and the above mentioned families 

 they are situated midway between the compound eye and the centre of 

 the head, and the basal joints are therefore contiguous. The ocelli, too, 

 are situated at a distance from the compound eye, and from the base of 

 antennae, and are often unusually large and prominent. In the Noc- 

 tuidae they are close to the compound eye and close to the base of an- 

 tennae so that in most cases they are easy discernible with a lens without 

 denuding any portion of the head. No Boinl-ycid. genera have been 

 compared, for that would have exceeded the purposes of this paper. 



The families above discussed can be separated in tabular form so as to 

 give a convenient comparative survey, as follows : 



Primaries with two internal veins. 



Secondaries with costal vein connected with subcostal by an obli'juc branch; 



with two or three internal or free veins Z.vgaeiii<Iae. 



Secondaries without costal vein ; Pyroiuorphidae. 



Primaries with a single internal vein; secondaries without costal vein. 



Secondaries with a single internal vein, and not more than a total of 7 veins. 



Syntomoidae. 

 Secondaries with two internal veins; always with 8 veins Cteiilictiidae. 



