SOME AMERICAN GEOMETRID MOTHS — CAPPS 121 



Remarks. — The species of Lartibdina closely resemble those of 

 Neothcrina but are easily separated by genitalic characters. In 

 Lambdina the aedeagus is without a distoventral sclerotized furcate 

 plate ; there is no concave sclerotized band bordering the ventral mar- 

 gin of the female genital opening and the central area of the signuni 

 is without spines and comparatively smooth. 



Because of variability in color, maculation, and genitalia within 

 the genus it is impossible to make satisfactory keys. The following 

 keys are offered merely to help in identification of the species and 

 should be used with caution. For similar reasons it is impracticable 

 to include subspecific categories and these are omitted from the keys. 



KEY TO SPECIES OF LAMBDINA 



Males 



1. American species north of Mexico 3 2 



Mexican and Central American species 4 



2. Furca long, slender, laterally compressed 3 



Fnrca short, stout, not compressed 14. punctata (Hulst) 



3. Fore wing with transverse lines evenly curved, diffuse or rather 



indistinct, accentuated by fuscous dots on veins 9. athasaria (Walker) 



Fore wing with transverse lines sinuate, rather sharply defined, 

 if nearly straight or evenly curved not strongly accentuated on 

 veins by fuscous dots 2. fiscellaria (Guenee) 



4. Fore wing broad; transverse lines indistinct, accentuated by 



fuscous dots on veins. Aedeagus somewhat extenuated pos- 

 teriorly ; a large patch of cornuti 13. negata (Dyar) 



Fore wing narrower ; transverse lines rather distinct, only slightly 

 if accentuated on veins. Aedeagus strongly extenuated pos- 

 teriorly; a small patch of cornuti 7. axion (Druce) 



Females 



1. American species north of Mexico 2 



Mexican and Central American species 4 



2. With ventral operculum strongly sclerotized 3 



Without a strongly sclerotized ventral operculum 14. punctata (Hulst) 



3. Fore wing with transverse lines evenly curved, diffuse or rather 



indistinct, accentuated by fuscous dots on veins 9. athasaria (Walker) 



Fore wing with transverse lines sinuate, rather sharply de- 

 fined, if nearly straight or evenly curved not strongly accen- 

 tuated on veins by fuscous dots 2. fiscellaria (Guenee) 



4. Ductus bursae at least three times as long as posterior internal 



band 7. axion (Druce) 



Ductus bursae shorter, less than three times length of posterior 



internal band 5 



5. Posterior internal band of ductus bursae extenuate posteriorly 



8. calidaria (Dyar) 



Posterior internal band of ductus bursae not extenuate pos- 

 teriorly 13. negata (Dyar) 



8 The Hiibner species, fervidaria, is omitted because the type lias been lost, and there 

 is no certainty as to just what it represents. 



