8 



which the characters above mentioned were still those of the genuine 

 apple plant louse. This similarity was evidently due to the general 

 dryness of grasses common during summer, whereas from September 

 till winter and the following spring, grasses as well as grain became 

 more succulent and nourishing, with the result that nectaries as well 

 as antennae developed more rapidly as the season and growth of plants 

 advanced. These organs reached their maximum development toward 

 the end of June, after which a general retardation set in, until the 

 sexupares or return migrants were almost identical with those found 

 on the apple during the spring, though stray specimens may fre- 

 quently be encountered during the season, which indicate an over- 

 lapping of two different series. 



The annexed list is for the purpose of indicating the localities and 

 plants on which the grain louse has thus far been observed: 



Apple (Pur us mains), United States, April to June, and September to November. 



Pear (Pyrus communis), Washington, D. C, October and November. 



Hawthorn (Crataegus coccinea, etc. ), Washington, P. C, May and November; New- 

 ark, Del., November. 



Quince (jCydonia vulgaris), Washington, D. C, May and November; St. Louis, 

 Mo., June. 



Plum (Prunus sp. ?), Washington, D. C, June; Kichfield Springs, N. Y., May. 



Choke cherry (Padus virginiana) , Oakwood, Nebr., October. 



Wild black cherry (Padus serotina), St. Louis, Mo., October. 



Dogwood (Cornussp. ?), St. Louis, Mo., October; evidently accidental. 



Celery (Apeum graveoleus), Washington, D. C, November; with larva?. 



Tickseed ( Coreopsis. sp. ?) Brookings, S. Dak., September; with larva?. 



Shepherd' s-plirse ( ( 'apst lla bursa-pastoris), Washington, D. C, November; probably 

 accidental. 



Burdock (Lappa major) , Washington, D. C, November; accidental. 



Wheat (Triticum vulgare), Washington, D. C, March to June; Pocomoke City, 

 Md., April; Adonia, Xa.., April; Trenton, N. J., May; Massachusetts, November; 

 Carroll, Ohio, October, November; Wooster, Ohio, January; Lafayette, Ind., June; 

 Laporte, Inch, December; Sherman, Tex., April; Los Angeles, Cal., April; Cham- 

 paign, 111., November. 



Bye (Secale cereale) , Atlanta, Ga., April. 



Oat (Arena sativa), Washington, D. C, November; St. Louis, Mo., November. 



Meadow grass (Poa pratense), Washington, D. C, October to December 



Bluegrass (Poa compressa), Ashland, Nebr., October. 



Timothy (Phleum pratense), Washington, I). C, August, November. 



Finger grass (Panicum singuinale), Washington, D. C. August, November. 



Orchard grass (Dactyl is glomerata), Richfield Springs, N. Y., October. 



Upright chess (Bromus racemosus), Washington, D. C, June. 



Rescue grass (Bromus unioloides), Washington, D. C, January, 1903. 



Thus far 22 plants are herewith recorded on which the species has 

 oeen observed, of which S are trees, -i are weeds or herbs, and 9 grains 

 or p-rasses. 



