220 



BEUTENMULLER, MONOGRAPH OF THE SESIIDAE. 



shifted from place to place by various authors, and it has not as yet found a defi- 

 nite systematic position. 



Linne (1758) placed the species in the Sphingidse, but they were arranged 

 by subsequent writers between this family and the Zygaenidse, in which position 

 they were left undisturbed for many years. Newman in 1832 called attention to 

 the relationship of the Sesiidae to the Cossidae and Hepialidae, and in 1878 Butler 

 attempted to prove their affinity to the Gelechidae, in which group they were also 

 placed by Meyrick in 1895. Dr. Dyar, the latest writer on the subject, likewise 

 arranges them in the lower families of the Heterocera, in which position they 

 are more apt to fit than in the higher families of this order, as placed by the 

 earlier writers on the subject. 



At any rate, no matter where they may be placed hereafter, the members of 

 this family, in the course of their evolution, have progressed far from the primi- 

 tive type of the order, as pointed out by Professor Comstock. The species have 

 kept closely together, and there is less variation in the structure of the wings and 

 other organs than one would expect to find in a group so highly specialized. 



Characters of the Family. 



Head small, eyes naked ; ocelli present. Labial palpi moderately long, curved, ascending, 

 rarely porrect, terminal joint short, pointed. Maxillary palpi rudimentary. Proboscis well devel- 

 oped or rudimentary. Antennae long, gradually dilating from about the middle to near the apex, 

 thence rather pointed, sometimes almost filiform ; ciliate or pectinate in the male, simple in the 

 female. Abdomen elongate, slender, narrow, rarely robust, and provided with a fan-like anal tuft 



orwithpencilsinmale. 

 Anal tuft of female 

 bunch-like or almost 

 wanting. Legs often 

 with thick tufts of 

 hairs. Mid-tibiae with 

 onepairof spurs; hind 

 tibiae with two pairs. 

 Fore wings, elongate, 

 narrow, more or less 

 transparent or opaque, 

 with 11 or 12 veins, 

 R 4 and R 5 usually 

 stalked ; vein 2d A 

 present. Hind wings 

 elongate, ovate, with 

 three internal veins. 

 Frenulum consoli- 

 dated ; similar in 

 both sexes. 

 Regarding the wings of the Sesiidae, Prof. John Henry Comstock writes me 

 as follows : 



" The wings present several striking characteristics :— the loss of scales from a greater or less 

 portion of the surface ; the narrowness of the fore wings ; the great reduction of the anal area of the 



Fig. 



Wings of a Pupa of Sanninoidea exitiosa, showing the Tracheae of the W 



ing-veins. 



