6 BULLETIN 112, U. S. DEPARTMENT OF AGRICULTURE. 



winged female has its wing venation much like that, of Aphis pomA; 

 the cornicles are black, tapering and reaching almost to the tip of 

 body, and the abdomen is rather conspicuously marked by a large 

 black patch on the dorsum. 



HOST PLANTS. 



Aphis avence has been recorded from a large number of plants, par- 

 ticularly of grasses. Owing to the confusion with the larger grain 

 aphis (M acrosiphmn granarium) in some of the literature, it is im- 

 possible in many cases to determine which species of plant-louse was 

 meant, and consequently the following list includes only those plants 

 in cases where the identity of the aphis is reasonably certain. This 

 list does not include all of the plants upon which this species has been 

 found in Europe. 



GRAMINE^E. 



Wheat, Triticum vulgar e 



Triticum dicoccum 1 

 Rye, Secale cereale 

 Oat, Arena sativa 

 Wild oat, Avena fatua 2 

 Tall oat grass, Arrhenatherum ela- 



tius 3 > 4 

 Barley, Hordeum vulgarc 

 Two-rowed barley, Hordeum distichon ' 2 

 Wall barley, Hordeum murinum i 

 Timothy, Phleum praterise. 

 Canada blue grass, Poa compressa 

 Kentucky blue grass, Poa pratensis 

 Annual or dwarf meadow grass, Poa 



annua l 

 Rough-stalked meadow grass. Poa 



trivialis 

 Crab grass, Syntherisma sanguinale 

 Upright chess, Bromus racemosus 

 Rescue grass, Bromus imioloides 

 Cheat, Bromus secalinus 3 > 4 

 Hungarian brome grass, Bromus in- 



ermis 3 > 4 

 Orchard grass, Dactylis glomerata 

 Italian rye grass, Lolium multiflo- 



rum 3 > 4 

 Perennial rye grass, Lolium perenne 3 > 4 

 Redtop, Agrostis alba 3 > 4 

 Red fescue, Festuca rubra 3 » 4 

 Sheep's fescue, Festuca ovina 3 > 4 

 Meadow fescue, Festuca pratensis 



[=elatior] 3 > 4 



GRAMINEiE Continued. 



Hard fescue, Festuca ovina durius- 



cula 3 > 4 

 Reed canary grass, Phalaris arundi- 



nacea 3 > 4 

 Melic grass, Melica bauhini 1 



Melica penicillaris 1 

 Johnson grass, Andropogon halepensis B 

 Broom corn, Andropogon sorghum var. 

 Sorghum, Andropogon sorghum var. 

 Koeler's grass, Koeleria cristata 1 

 Wild rye, Elymus geniculatus [=are- 



narius] 1 

 Virginia wild rye, Elymus virginicus * 

 Nodding wild rye, Elymus canadensis* 

 Corn. Zea mays 

 Teosinte (Euchlaena mexicana) 3 » 4 



TYPHACE^E. 



Cat-tail, Typha latifolia 4 



AMMIACE^E. 



Celery, Apium graveolens 



COMPOSITE. 



Tickseed, Coreopsis sp.? 

 malace.^:. 

 Apple, Mains malus 



avenw Fabr. 



io record on this plant from 



1 Recorded by Mordwilko as hosts of Aphis padl Kalt 



3 Recorded by Fabricius ; so far as known, there i 

 America. 



3 In 1909 Mr. T. H. Tarks, at that time connected with the Bureau of Entomology, con- 

 fined this species with various plants and found that it would breed contentedly and freely 

 on these plants. Other plants tried, and which the aphides refused, are Muhlenbergia, 

 Auropyron occidentale, Panicum virgatum, and P. bulbosum. 



1 Recorded here for the first time. 



5 Recorded as hosts of this species by Passerini. 



