AMERICAN I.KriDOl'TERA. 319 



in some cases, wliere the peeiiliiiritv seems to be in the process of 

 development, or where perhaps the species is outgrowing it. Some- 

 times it is large and prominent, consisting of an unsealed vitreous 

 surfjice, at times with a peculiar gland within it. 



There is wide variation in the structure of the antenna? not only 

 in tiiat bipectinate, lamelate, fascicled, ciliate, filiform and flattened 

 forms are found, but also in the location of the various appendages. 

 In many species the i)ectinations are at the summits, in othei's at the 

 bases of the segments. The rule is not invariable, but generally the 

 species having the fovea on the fore wings of the males, have also 

 the pectinations or fascicles on the top of the segments of the antennse. 



A[)art from the elements of structure upon which the subfamily 

 is founded, there is among the species a very wide range of variation. 

 The i)alpi, clypeus, antennie, legs, thorax, abdomen and wings vary 

 greatly ; especially is the venation subject to variation not only in the 

 different species, but in the individual species. In view of this, in the 

 main, very little dependence can be placed upon the relations of veins 

 9, 10, 11 and 12 to each other in the fore wings. Not infrequently an 

 extra vein (vein 13) is found, and very frequently 11 is present or 

 absent in different specimens of the same species; 9, 10, 11 and 12 

 anastomose with each other, or are separate in the individuals of one 

 species, and as a conse(iuence vei-y little use can be made of them iu 

 classification. The position of the bases of the veins are much less 

 variable. The hind wings are less changeable in venation than the 

 fore wings, but the comparative positions of 3 and 4, as well as 6 

 and 7, cannot be relied upon within narrow limits. 



Synopsis of Genera. 



1. Fore wings of % witli fovea below at base of 1« 2. 



Fore wings of % without fovea below at base of la ;J6. 



2. Antenna- of % t)ii)ectinate : 3. 



Antenna' of % not bipectinate 30. 



3. Tongtie absent, or very short 4. 



Tongue develoi)ed, at least one-half thorax 5. 



4. Hind tibise with one pair of spurs 63. Xacophora. 



Hind tibia? with two pairs of spurs 34. Aiiiilapis. 



5. Fore wings ^-ith discal scale tuft 44. Tornos. 



Fore wings without discal scale tuft (i. 



t). Clypeus tubercled 7. 



("lyi>eus not tubercled 11. 



7. Fore tibiae clawed 8. 



Fore tibise not clawed 49. Ccenocltaris. 



TRANS. AM. ENT. SOC. XXIII. SEPTEMBER, 1896. 



