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large insect, the middle of secondaries semi-transparent, and tiie outer 

 margin of primaries even. The third joint of palpi is produced in the 

 form of a small curved horn. Dilphonota contains smaller species with 

 dentate outer margin of primaries, and the thorax with a distinct divided 

 crest. The latter structure is peculiar to this genus so far as I know, 

 among the N. A. representatives of the family. 



These two genera really belong nearer to the true Sphinges than 

 Pachylia and allies; but are placed here merely for convenience of com- 

 parison. 



In the remaining genera of this series, a long step is made to the 

 Smeri7ithids in the weak legs with the small spurs of the middle and hind 

 tibia. The head is as in the Sphi?iges and the thorax is rather shorter 

 than in that group. 



Chccrocampd has short narrow primaries and an unusually long 

 slender, conic abdomen. The secondaries also are very narrow, and ex- 

 cavated before the anal angle. The species are of the most elegant in 

 our fauna. 



Darapsa has wider wings and heavier, shorter abdomen, the thorax 

 is proportionately weaker, and the head more retracted. The wings are 

 much as in Philampdus. I cannot separate Ampelophaga versicolor from 

 this genus. 



Deidamia is one of the connecting genera between this group and the 

 Srneriiithids. The head is retracted, the (^ antennae serrate, the primaries 

 shaped like Smerin/hus. But the tongue is distinct and for this reason 

 1 place it at the end of the present series. 



The Smeriuthides are distinguished by the short membraneous 

 tongue, retracted head, serrate or pectinate antennse of the (^, usually 

 angulated or scolloped primaries, less conic and more obtusely terminated 

 abdomen, which is also more woolly and less smoothly clothed than in 

 the preceding group, and by the weak short legs in which the spurs are 

 greatly reduced in size and often wanting in part. The posterior legs are 

 much reduced in length and strength, and mstead of being the most 

 robust, they are in this series the weakest pair. As a whole the tendency 

 to the Bombycidc£ is unmistakeable and very strongly marked in every 

 respect. 



The genera are closely related and with the exception of Arctonoius 

 and Ellema which I class with this series, they are often lumped under 

 the generic type Srnerinihus . 



Tripiogon contains two large species, moaesta and occidenialis, with 

 very strongly retracted head, scolloped outer margin of primaries, and a 

 heavy claw terminating the tip of fore tibia. The middle and hind tibiae 

 have each two small spurs at tip. The secondaries are not ocellated. 



