255 



on the windows of houses, particularly in the evening", and they are 

 readily attracted to lights. 



In Britain many species of this and allied genera occur during 

 winter in clumps of grasses and ferns overhanging streams and 

 ditches, and this fact seems to indicate that they hibernate as adults. 



Exec HI A NATiVA Johannsen 



Exechia natka Johaimseii, Bull. 200 Maine Art. Exper. Station, p. 70. (1912) 



Larva (PI. XXXVII. Fig. 3).— Length, 8-9 mm. White, head 

 and locomotor spinules black. 



Head as in Figure 7, Plate XXXVII ; mandibles different from 

 those of Leia in having 9 sharp teeth distributed along their entire out- 

 er margin (Fig. 6) ; maxillary palpi much longer than in Leia (Fig. 

 9); hypopharynx as in Figure 11. Thoracic spiracles each with 4 

 slit-like openings (Fig. 4) ; abdominal pairs smaller than the thoracic. 

 Locomotor spinules arranged as in Figure 2, Plate XXXVII, the 

 apices of the spinules in the anterior and posterior series directed 

 respectively cephalad and caudad. 



Pupa (PI. XXXVII, Fig.- 12). —Length, 4-6 mm. Color at first 

 like that of larva, but later becoming darker, and just before the 

 emergence of the adult the color of the latter is clearly discernible 

 through the pupal skin. 



Head vmarmed, slightly more retracted than in Leia ; antennae ex- 

 tending beyond middle of wings; palpi directed straight laterad. 

 Thoracic respiratory organs sessile ; wings extending to middle of 

 fourth abdominal segment ; legs extending to apex of abdomen, end- 

 ing in an almost straight transverse line. Abdomen without arma- 

 ture; spiracles slightly elevated. 



Described from specimens I collected from the stems of a species 

 of Agariciis in the forestry of the LTniversity of Illinois, at LTrbana, 

 in September, 191 5. 



The effect of parasitism upon the pupa is shown in Figure 15, 

 Plate XXXVII, the larval skin having been shed but the formation 

 of the pupa prevented. 



Subfamily SCIOPHILINAE 



This subfamily is unknown to me in the immature stages except 

 by the larval exuvium and the pupae of one species and from pub- 

 lished descriptions (^f the larvae of others. The tracheal system of 



