NORTH AMERICAN LEPIDOPTERA. 117 



CJuerocampa has a very long abdomen ; narrow, graceful wings 

 and slender antennae, with a small hook at tip. It finds a close ally 

 in jE/hpos. 



Argeus is allied to Chdcw&oapii by the slender antenna-, with a 

 somewhat longer hook at tip. The head is large and prominent, and 

 the body slender and graceful. The wings are rather narrow, the 

 excavation of outer margin well marked. 



Tlie other genera have the antenme fusiform, with a long, recurved 

 hook at tip, or without any perceptible hook, the end being merely 

 somewhat curved. 



Pachylia is a heavy form with sombre coloring, obtuse abdomen 

 and broad wings. 



Philampelus is closely allied, but more graceful ; with larger, more 

 pointed abdomen, narrower wings and entirely diflerent genitalia. 



Ampeloj)haga contains smaller forms with short, slender antennae, 

 much more sinuate primaries and weaker legs. This genus makes a 

 very decided approach to the Smerintkid type of structure. 



Three of the genera, — Pachylia, Philampelus and Argeus are rather 

 closely allied, the diflTerences being principally comparative. They 

 are recognizable by somewhat different habitus as well as by the 

 differences heretofore jjointed out. 



Pachijlla seems better marked than Argeus, but of the latter I have 

 had no % for dissection. 



In tabular form, the scheme outlined above, would be as follows : 



Ahdomt-ii with a fan-like tuft at tip. 



Primaries not angulated .Ellopos. 



Primaries angulated. 



Thorax prominently crested Eiiyo. 



Thorax not crested. 



Body not depressed ; head distinct ; ahdomen not laterally tufted. 



Aiiipliion. 

 Body heavy, depressed ; head retracted ; abdomen with a series of trun. 



cated lateral tufts Til ;»■ reus. 



Body slender; head retracted, with a distinct frontal crest; vestiture thin. 



Deidauiia. 

 Abdomen not tufted. 



Antennae gradually thickened to tij), not clul)l)ed. 



Anterior tarsi with first .joint armed with stout spines outwardly. 



I>4'ile|>liila. 

 Antennse slender, a small recurved hook at tip. 

 Anterior tarsi unarmed. 



Ahdomen elongate, slender; wings narrow, pointed, graceful. 



C'lKX'riicanipa. 



Abdomen shorter, wings broader, anal angle well marked; antenn;e with 



longer hook at tip ; head large, prominent Argeusi. 



