A NEW SPECIES OF TOXOPTEEA. 9 



DISTRIBUTION OF TOXOPTERA MUHLENBERGLE. 



This aphis has hecn found through northwestern and west-central 

 Ohio and through east-central and northern Indiana. It pro})ably 

 may be found in any location in which Muhlenbergia flourishes. 



FEEDING HABITS. 



Individuals of this species concentrate on the tender shoots and 

 are rarely found on the tough leaves unless the ])lants are badly 

 infested. They congregate in the curled central growing shoot. As 

 this leaf expands and unfolds, they go to the younger curled leaf just 

 below this. When in great numbers, they cause these tender shoots 

 to wilt and turn yellow. 



HOST PLANTS. 



l^p to the present time Muhlenbergia sp. appears to be the normal 

 host, though this aphis often goes to bluegrass {Poa pratensis) when 

 first hatched, since the young sometimes appear before Muhlenbergia 

 has started growth. Colomes have been established on wheat, though 

 they do not appear to thrive very well on it, 



LIFE HISTORY. 



As stated previously, the sexes were reared in October, 1908, at 

 Richmond, Irid. A number of eggs was obtained from these females 

 and they were taken to I^a Fayette, Ind., in March, 1909, but failed to 

 hatch. Later on in the year these aphides were found in abundance 

 and rearings were begun, with the result that a large number of the 

 sexes and an abundance of eggs were obtained in the fall. 



CONTINUOUS-GENERATION EXPERIMENTS. 



About 1,000 eggs were collected in the fall of 1909 with the hope 

 of getting stem-mothers to start a series of continuous generations. 

 None of these eggs hatched, however. Large numbers of eggs were 

 found in the field and from these the continuous-generation series 

 were started; that is, starting with the stem-mother and isolating her 

 first born and the first born of each successive generation until the 

 sexes appeared; and a second series, consisting of the last born from 

 the stem-mother and the last born of each successive generation until 

 the sexes appeared. By adding the number of first and last born 

 generations and dividing the result by 2 we are able to arrive at the 

 approximate number of generations that would be produced during 

 the year. Much other data would also be accumulated in this way 

 on the daily production of young, the maximum and minimum num- 

 ber of young produced, and the avcM-age length of life. 



The table follo\\'ing gives in detail the consecutive generations of 

 the first and last born series, starting with a stem-mother that 

 hatched March 28, 1910. 



