No. 34- J HEMIPTERA OF CONNECTICUT: APHIDIDAE. 



299 



Hyalopterus Koch. 



H. arundinis (Fabricius). Aphis arundinis Fabricius. Apkis 

 priini Fabricius. 



Syst. Ent, 734, 1775. 



This species migrates between plum and reed grass. For 

 description and figures see Patch (1914b). Also see Gillette and 

 Bragg (1910). 



On European plum. 



New Haven, July, 1901 (W. E. B.). 



Hyadaphis, Liosomaphis, Rhopalosiphum and Siphocor5^.e- 



The species of this group are so woefully tangled as to generic 

 synonymy and are so closely affiliated by connecting forms, thai 

 it is easier to key them together than to attempt to separate them 

 on generic characters. 



Key to Species. 



1. Hind wing not extraordinary j2 



Hind wing minute serotiaae 



2. Species developing on vegetation other than grasses for at least part 



of the annual cycle 3 



Species developing on grasses (Family Gramineae) for at least a 

 part of the annual cycle. Cornicle weakly swollen, with distinct 

 constriction before flange prunifoliae (avena^) 



3. Species developing on one or more plants of the family Rosaceae 



for at least a part of the annual cycle 4 



Species developing on vegetation other than Gramineae and Rosa- 

 ceae for at least a part of the annual cycle 3 



4. Dark brown or wine-colored species on Primus nymphaeas 



Delicate green or yellowish species commonest on Pyriis. Cor- 

 nicle weakly swollen with distinct constriction before flange . . . 



prunifoliae (avercisj 



5. Caudal horn present 6 



No caudal horn 8 



6. Filament of vi shorter than iv -{- v 7 



Filament of antennal segment vi longer than iv + v. Species on 



Salix or various genera of the Umbelliferae pastinacesje 



7. Antennal segment iv without sensoria. Species on Salix or various 



genera of the Umbelliferae caprcae 



IV with sensoria. Species on Umbelliferae cicirtz* 



8. Species which may develop on Umbelliferae for at least part of 



the annual cycle 9 



Species either never reported from Umbelliferae or with other 

 hpst plants as well 10 



9. Antenna of alate female rather thickly set with tuberculate sen- 



soria. General color pale green. Cauda of apterous form large, 



long and broad xylosl^i 



Antenna of alate female with secondary sensoria usually confined 

 to more or less crowded and irregular row on segment iii. Gen- 

 eral color brown, wine or if green then not pale. Cauda of 



apterous form not unusual nymphseae 



10. Filament of vi distinctly longer than base u 



