CLEAR-WING MOTHS OF FAMILY AEGERIIDAE 3 



modifications, especially of the posterior tibial and first tarsal joints, are 

 useful as generic characters; these joints are very long in Podosesia, and 

 the first tarsal joint, normally smooth, is thickened with rough scales in 

 some genera {Alcathoc, Synanthedon). 



The male genitalia exhibit many modifications, not always easy of 

 interpretation. In the genera that are considered the more primitive 

 {Bemhecia and Aegeria) the uncus is short, divided, and hairy at the tip, 

 suggesting socii. In the higher forms (Pamnthrene group) the uncus 

 becomes more elongate, still divided at the tip and with lateral sociuslike 

 hairy pads at tip. In the genera regarded as most highly developed 

 {Synanthedon group) the uncus is fused with the tegumen and is de- 

 veloped at the apex into large backwardly curved flaring pads, thickly 

 covered with characteristic forked hairs, and very suggestive of socii, so 

 much so that they have repeatedly been considered as such (Busck, Proc. 

 Ent. Soc. Washington, vol. 31, p. 135, pi. 7, 1929). It is, in fact, still de- 

 batable whether this structure represents uncus or socii or a combination 

 of both, but in this treatise it will be designated uncus. 



The gnathos is more or less well developed normally, especially in the 

 higher forms (Synanthedon group) continued in a narrow, wirelike, 

 undulating \ entral plate supporting the underside of the bulging alimentary 

 canal. 



The anellus is normally a small (in Bemhecia large), triangular or 

 rectangular plate with two lateral processes, supporting the retractable tube 

 surrounding the aedeagus. 



The aedeagus is normally long, slender, straight or undulating, often 

 with a bulbous base and with short spines on or near the tip; the apex 

 sometimes furcate or swollen. 



The cornuti are normally present as short, often paired, thorns, but in 

 some species merely as granulation. 



The vinculum is long or short, strongly sclerotized, sometimes broadened 

 and furcate at tip. 



The harpes in the more primitive genera {Aegeria) are short and 

 stubby, more or less quadrangular, with strong bristles on end near the 

 edges. In the higher genera {Paranthrene group) the harpes are more 

 elongate, rounded, with edges long-haired or spined, sometimes with 

 forked spines on costal edge and on sacculus. These hairs are triforked or 

 multiforked in contrast to those of the Synanthedon group, which are al- 

 ways bifurcate. In the highest groups (Synanthedon and allies) the 

 harpes are elongate-ovate, sometimes with pointed apices, and the costal 

 and terminal half is thickly covered with characteristic forked spines, 

 similar to those on the uncus; these spines are shortly bifurcate and .black- 

 ened in the cleft ; sacculus with a more or less naked basal area, bordered 

 costally by an oblique ridge (here designated "sacculus ridge") with 

 prominent scales or thorns of various forms ; the modifications of this 



