97 



the Yponomeutidae, the only important differences between the two 

 famihes being the freedom of the seventh abdominal segment in the 

 male and the presence of a very short cremaster in the Epermeniidae. 

 Another difference is that in Epermeniidae the wings and other appen- 

 dages are somewhat elevated at the meson and slope to each lateral 

 margin. A comparison of Figure 68 with Figures 82, 83, and 85 

 will show the similarity in arrangement of parts in the Yponomeutidae 

 and Epermeniidae. 



The following species was examined : 

 Bpcrmcnia pimpinclla Murtfeldt. 



Family Yponomeutidae 



The genera comprising this family resemble each other very 

 strongly in all important characteristics, but nevertheless possess very 

 clear generic distinctions. They closely resemble certain of the gen- 

 eralized gelechiids (Figs. 88, 89), and many authors have associated 

 those genera with the yponomeutids. The presence of a distinct 

 fronto-clypeal suture and the peculiar arrangement of the antennae in 

 the family Gelechiidae, together with the apparent loss of the labial 

 palpi, seem to separate it very clearly from the Yponomeutidae, in 

 which the fronto-clypeal suture is never distinct and the antennae are 

 never adjacent on the meson except in Zelleria (Fig. 82). The typical 

 arrangement of parts is seen in Figures 82, 83, 84, 85, 86, making 

 further description unnecessary. The abdominal spiracles are all con- 

 siderably produced and tubular, being longest in Plutella. There is no 

 cremaster present in any of the genera. The genera of Yponomeuti- 

 dae may be separated by the following table : 



a. Mesothoraeic spiracles produced, tube-like ; setae at caudal end of 

 tenth segment hooked; maxillae more than three fourths the length 



of the wings Plutella Schrank. 



aa. Mesothoraeic spiracles not produced, slit-like; setae at caudal end 

 of tenth segment straight, or occasionally slightly curved at end; 

 maxillae much less than three fourths the length of the wings, 

 b. Caudal end of tenth segment showing four straight setae, generally 

 two directed laterad and two caudad ; maxillary palpi touched by 

 both prothoracic and rnesothoracic legs. 

 c. Maxillary palpi long, reaching the proximo-lateral angles of the 

 maxillae ; labial palpi never becoming wider than at their prox- 

 imal margin; antennae never touching on the meson. 



Yponomeuta Latreille. 



cc. Maxillary palpi short, never reaching the proximo-lateral angles 



of the maxillae ; labial palpi wider through most of their length 



than at the proximal margin ; antennae touching on the meson. 



Zelleria Stainton. 



