A SYNOPSIS OF THE APHIDIDAE 139 



1. Winged forms with a cucurbit-shaped cauda. Nymphs that failed to molt 



with three-jointed antennae. Winged forms with three to five-jointed 

 antennae, which are coarsely ringed from the third on. Wingless partheno- 

 genetic females presenting the appearance of the larvae of other families, 

 as of some kinds of Coccidae, or of species of Aleyrodes. Sexual forms 

 with beaks Group Hormaphidina 



Winged forms without distinct cauda. Nymphs that failed to molt with four 



to five- jointed antennae. Antennae of winged females five-to six- jointed. 

 Sensoria may be found on the third and following joints, often in the 

 form of arches or half rings, but never as complete rings 2 



2. Cubitus [third discoidal vein] of the fore wings simple. Cornicles, which are 



pore or pointlike, present only in some species, and then not in all forms. 



Group Pemphigina 



Cubitus [third discoidal vein] of fore wings once-branched. Cornicles mostly 



point or pore-like 3 



3. Antennae of winged forms six-jointed. Wings held roof-like when at rest. 



Group Schizoneurina 



Antennae of winged forms five-jointed. Wings held flat when at rest. 



Group Vacunina 



Group Hormaphidina Mordw. 



Mordwilko, Ann. Mus. Zool. Imp. Acad. Sci. St. Petersburg, vol. 13, pp. 

 364-365, 1908. 



The antennae of the winged forms are 5- to 3-jointed (?). With the exception 

 of the first two joints they are closely and entirely ringed. Even in the genus 

 Hormaphis O.-S., where the antennae are 3-jointed, they may probably be con- 

 sidered morphologically as of five joints. The wings are held flat at rest. There 

 are four transverse veins on the fore wings, the third of which [third discoidal] 

 is simple. The first two [first and second discoidals] originate at the same point 

 on the subcosta. The hind wings have one or two transverse veins, in the latter 

 case both originating at the same point. The wingless parthenogenetic females 

 on the alternate host plants (for example on birch) are mostly circular in shape, 

 and have small wax tubes around them. Other forms are coccid-like. The sexual 

 forms have beaks. The cornicles are absent. 



This is a description as given by Mordwilko in the above mentioned 

 paper. Below is a key to the genera, as given by Mordwilko and by 

 Van der Goot, the latter of whom includes in this group the two 

 genera Hamamelestes Shimmer and Ceratophis Licht. 



1. Antennae of winged females plainly five-jointed 2 



Antennae of winged females only three-jointed Hormaphis O.-S. 



2. Antennae always five-jointed. Front of head always with two little horns. 



Third discoidal once-branched Cerataphis Lichtenstein 



Antennae of apterous forms three- or four-jointed. Front without horns. 



Third discoidal simple Hamamelistes Shim. 



