82 ILLINOIS BIOLOGICAL MONOGRAPHS [82 



farther laterad than alpha except on segment 8 where they are at about 

 the same level, and segment 9 where it is farther mesad ; kappa, eta, 

 and mu on segment 9 located on the same pinaculum. Thoracic legs 

 adjacent, prolegs short, each bearing a complete circle of biordinal cro- 

 chets ; anal prolegs bearing a single series of crochets on the cephalic 

 ■margin. 



Stenoma humilis has a small head, uniform in color and less than 

 one-third the diameter of the body, while in $. schlaegcri and »§. brillians 

 Busck the head is about two-thirds the width of the body and is trans- 

 versely striped, the stripe continuous in the former but broken and 

 dotted in the latter. 



Gonioterma albamim of Europe differs from the American species 

 in that the Kappa group on segments 7 and 8 is cephalo-ventrad of rho 

 while in Stenoma it is directly ventrad. 



Family Hemerophilidae 



Several important differences may be noted, distinguishing the lar- 

 vae of this family from those of the Yponomeutidae, in which they have 

 long been included. The most important is the close association of 

 kappa and eta on the abdomen and the relative position of alpha and 

 beta on the prothorax. 



Head longer than wide ; front much longer than wide, acute at 

 caudal end, extending more than half way to vertical triangle ; adfront- 

 als narrow; ocelli all close together. Prothorax with alpha farther 

 laterad than beta, rho distant from epsilon, Kappa group trisetose, and 

 Pi group unisetose as usual; metathorax similar. Abdomen with spira- 

 cles round or broadly elliptical, beta farther laterad than alpha on all 

 segments except 9, where alpha is usually much farther from dorsome- 

 son ; kappa and eta adjacent. Prolegs long and slender, with either a 

 complete circle or mesoseries of uniordinal crochets, often poorly 

 developed. 



Pour of the genera belonging to this family have been examined 

 in the larval stage. 



Choreutis leucobasis. Crochets rudimentary, arranged in a com- 

 plete circle ; Pi group on segments 2, 7, and 8 trisetose ; all setae poorly 

 developed; alpha and beta at about the same level on abdominal 

 segments. 



Allonyma (Hemerophila) vicarilis. Crochets strongly chitinized ; 

 setae well developed and borne on distinct pinacula ; otherwise similar 

 to Choreutis. 



Brenthia pavonacella. Crochets in a complete circle ; beta almost 

 directly ventrad of alpha on abdominal segments 1 to 8, caudad of 

 alpha on segment 9. 



