61 



extending down over the labial palpi for one fourth of their 

 length, 

 c. Appendages free, never firmly soldered to the body wall ; abdomen 

 always with some of the segments movable ; dorsum of the abdo- 

 men always with spines, 

 d. Abdominal segments 3-7 movable in the male, 3-6 in the 

 female ; antennae and metathoracic legs not approximately 

 equal in length and both seldom extending beyond the caudal 

 margin of the wings, 

 e. Labial palpi present ; caudal end of body ending in two stout 

 spines directed dorsad; abdominal segments 3-6 with the 

 two setae nearest the meson on the cephalic half of the seg- 

 ment so closely approximated that their bases touch. 



TlSCHERIIDAE. 



ee: Labial palpi never visible; caudal end of body never with 

 curved hooks, but the tenth abdominal segment with a 

 prominent lateral projection on each side ending in a stout 

 straight spine; abdominal segments 3-6 with the setae 

 nearest the meson at the cephalic end of the segment never 



closely approximated Bucculatrigidae. 



dd. Abdominal segments 4-7 movable in the male, 4-6 in the 

 female; antennae and metathoracic legs approximately of 

 equal length and both always extending beyond caudal mar- 

 gin of the wings, 

 e. Abdominal segments 3-7 never with two deep punctures or 

 pits with heavily chitinized edges on the meson at the 

 cephalic margin with one or more heavily chitinized spines 

 adjacent ; the length of abdominal segments 8-10 always 



greater than that of segment 7 Gracilariidae. 



ee. Abdominal segments 3-7 with two deep punctures on the 

 meson at the cephalic margin with one to three heavily 

 chitinized spines adjacent; abdominal segments 8-10 never 

 showing distinct segmentation, their total length less than 



that of the seventh segment Phyllocnistidae. 



cc. Appendages always firmly soldered to the body; dorsum of abdo- 

 men without visible spines ; abdomen without any movable seg- 

 ments Lyonetiidae. 



Family Nepticulidae 



These tiny species of leaf-miners average 2 mm. in length in the 

 females and 1.5 mm. in the males. The body is flattened, with a trans- 

 parent, slightly chitinized cuticle, and is white in color until the adult 

 scales are formed. Although their size makes it difficult to determine 

 the number of free segments, it is believed that there is some degree 

 of motion between all of the abdominal segments except the fixed 



