\362 The Zoologist— August, 18G8. 



Genus 1. Forda, Heyden. 



Antennae six-jointed; third joint much longer than the fourth; 

 sixth very short. Abdomen convex ; no nectaries nor tail. Tarsi 

 with two apical claws. 



Type, F.formicaria, Heyden. 



Genus 2. Rhizobius, Biirmeister. 

 Antenna? six-jointed; joints from the first to the sixth nearly equal 

 in length. No nectaries nor tail. Tarsi with one apical claw. 

 Type, R. Sonchi, Passerini. 



A. Sixth joint of the antenna; subclavate, longer than tbe fifth. . i. Sonchi. 



AA. Joints of the antenna; nearly equal in length. . . 2. Mentha. 



Tribe 5. Tychein.e, Passerini. 

 Genus 1. Tychea, Koch. 

 Antennae five-jointed, very short. Abdomen with a rim ; no nectaries 

 nor tail. Legs very short; tarsi with two apical claws. 



A. Joints of the antennae nearly equal in length. 



A. Body smooth. ...... 1. Eragroblidis. 



AA. Body pulverulent, setulose. .... 2. setulosa, 



AA. Joints of the antenna; various in length. 



A. Second and third joints of the antennae nearly equal in length ; 



fifth longer thau any of the others. . . . 3. Phuseoli. 



AA. Third joint of the antenna; longer than any of the others. 



a. Body pearly white, pubescent. .... 4. Selaritc. 



aa. Body luteous or orange, smooth. . . . .5. trivialis. 



Tribe 6. Cheemesin.e, Passerini. 

 A. Antennae five-jointed. 



A. Fore wings with four oblique veins, the cubital forked. . 1. Vacuna. 



AA. Fore wings with three oblique simple veins. . . 2. Chermks. 



AA. Antenna; three-jointed. .... 3. Phylloxeiia. 



Genus 1. Vacuna. 



Antennae short, five-jointed ; third joint longer than the others. 

 Wings horizontal. Fore wiugs with four oblique veins; the cubital 

 vein forked. Hind wings with one oblique vein. 



Typical species, Aphis dryophila, Schrank. 



A. Dorsum brown or green, with a pale stripe. . . . 1 . dryophila. 



AA. Dorsum greenish brown, with a white stripe and with white 



marginal spots. ...... 2. Alni. 



