68 ILLINOIS BIOLOGICAL MONOGRAPHS [68 



Head more or less depressed ; front triangular, not extending to 

 vertical triangle in American species ; boundaries of adfrontals extend- 

 ing to the vertical triangle on each side ; first and second ocelli usually 

 nearly contiguous, second, third, and sixth in a vertical row cephalad 

 of the fifth. Body cylindrical, incisions moderate. Prothorax with the 

 Kappa group trisetose, the three setae widely separated. Abdomen with 

 alpha much closer to dorsomeson than beta, rho located immediately 

 above spiracle, kappa some distance caudad of spiracle, and eta between 

 kappa and spiracle but located farther ventrad, or in some cases appar- 

 ently wanting. Thoracic legs present ; prolegs present on segments 3, 4, 

 5, and 6, each bearing a complete uniserial circle of uniordinal crochets. 



The above list of characters was drawn from specimens of Bedellia 

 somnulentclla and verified from Prolcucoptcra smilaciella, the only other 

 American species seen. Leucoptera (Cemiostoma) spartifoliclla of 

 Europe differs from them in the front, which reaches the vertical tri- 

 angle, and in the crochets, which are biserial in the caudal half of the 

 circle. 



SUPERFAMILY YPONOMEUTOIDEA 



Still retaining the ancestral, generalized arrangement of setae, the 

 few forms included in the Yponomeutoidea share with the Tineoidea 

 the distinction of being closely similar to Hepialus and the primitive 

 type. Altho a small group, the structure is extremely varied in those 

 characters which, in specialized forms, are constant in entire superfami- 

 lies. There are two families each of which includes larvae of at least 

 two strikingly different forms. Some authors consider Hemerophilidae 

 and Ethmiidae as relatives of this group but the larval structure indi- 

 cates a closer union with Gelechioidea. The same is true of the genus 

 Schreckensteinia. 



Family Heliodinidae 



It is clear that the "elachistid" genera now included here are more 

 closely related to Yponomeutidae than to any other families of the order. 

 Kappa and eta of the abdomen are distant, the Kappa group of the 

 prothorax is trisetose, with the three setae close together, and the front 

 extends somewhat over half the distance to the vertical triangle in some 

 species and reaches that triangle in others; the spiracle is small and 

 circular. 



Lithariapteryx nbroniaeella. Head scarcely depressed ; front short. 

 Abdomen with kappa and eta not on the same swelling, alpha directly 

 cephalad of beta. Crochets long, uniordinal or biordinal, arranged in 

 a complete circle. 



