-36 — 



Piionias has the outer margin .if primaries similarly crenulated, but 

 lacks the claw of the fore tibia. It is smaller, and has the secondaries 

 ocellate, differing from Smerinthus only in the outer margin of primaries. 

 Whether or not this ought to warrant the genus is a question, and in 

 the limited number of species in our fauna it should be considered rather 

 as specific than generic. 



Smerinthus has the primaries excavated and angulate and the second- 

 aries ocellate. The antennae of the $ vary in the length of the pectina- 

 tions; but the differences are specific and not generic. The tibia; are 

 unarmed and the posterior pair have only a single pair of small spurs at 

 tip. I cannot separate Calasymbolus Grt. from this genus. 



Cressonia is a very distinct genus. The palpi are long, the third 

 joints prominent, pointed and divaricate, the tibia? heavily spined, the 

 posterior with two pairs of spurs. The antenna? of the $ are bipectinate 

 in true bombyciform fashion. The outer margin of wings is dentate or 

 scolloped, but not prominently so. This is one of the most distinct of 

 the Sphingid genera, the palpi being abnormally developed, 



Arctonotus is a peculiar genus, which Mr. Grote classes with the 

 "Caudi&eres", and which in the armature of the fore tibia is related to 

 Pogocolon; but by the weak short tongue, the serrate and bristled <$ an- 

 tennae, and woolly body is nearer related to the Smerinthides. It seems 

 out of place anywhere. The primaries are small, stout, the outer margins 

 even. The posterior tibiae have two pairs of spurs. 



Ellcma is usually classed as a Sphingid genus but the tongue is 

 short, the legs are weak, and the posterior tibia have only a single pair 

 of spurs. The $ antennas are serrate and furnished with tufts of bristly 

 hair and the head is retracted. The outer margin is even, and the apex 

 somewhat rounded. 



Exedrium Grt., based on Sphinx halicarnim Strk. , probably comes 

 here. Mr. Strecker's description gives no structural details of any kind, 

 and I have only seen the insect to make a superficial examination of it. 

 It has a strongly bombycoid appearance, the wing form being much like 

 that of Hckrocampa and the body compact, robust. The tongue is prob- 

 ably weak, and the legs short. 



In synoptic form the scheme above developed is as follows: 



Tongue long, strong, corneous SPHINGIDES. 1 



Tongue short, weak, membraneous SMERINTHIDES. 8 



i Antennae clubbed at tip and furnished with a short bent hook , 2 



Antennae not clubbed, equal, or thickest at middle, either bent at tip or slender, 



curved 3 



2 Tibiae unarmed, wings more or less hyaline Macroglossa. 



Tibia: spinose, anterior armed at sides and tip Pogocolon. 



