245 



relation, in that the i>aiasit('s ^(MKMally issue from one to thret' weeks 

 before the eggs liatcli. (u- would have hatched. In Missouri, in 1.S70, 

 parasites issued ^Nfay aud young ^lantids May 14. In Washing- 

 tou, D. C, iu 1881, i)arasit('s issued ^lay 12 aud youug ^Nfantids May 

 21. In California, in 1888, parasites issued iu March from an egg mass 

 received from Japan, while the young ^Fantids made their ai)pearance 

 Ai)ril 16. Till' present year [)arasites issued iu Aju-il from egg uiasses 

 received from Vrizcma, fnuii which the young ]\Iantids issued May 18. 



NOTES ON THE GRAIN TOXOPTERA. 



{ToTopicrd tiram'nnim. K'oiiil. ) 

 I'.y F. M. Wki;stki:. 



This is a grain-affecting Aphidid which the V. S. Entomologist has 

 Deeu studyiug for some years. Though of foreign origin, without much 

 doubt, it has i)robably been a constant iithabitant of our grain fields 

 for a number of years, its numbers being too limited to attract atten- 

 tion, or it may have been confused with other species occurring in 

 nmch greater numbers. Bucktou* states that the species, during the 

 summer, inhabits Triticum, Hordeum, Avena, Sorghum, and Zea; but 

 at that time (1881) it was not known in England, and the literature at 

 my disposal does not indicate that it has since ajtpearedin that country. 

 That the s])ecies at times becomes exceedingly abundant is indicated by 

 Eondani's account of its appearance in 1853 " in tlui streets of Pjologna 

 iu innumerable swarms, to the annoyance of the inhabitants." t 



My own acquaintance with the species began early in July, 1884, while 

 studyiug the hal)its of Isosoma, at Oxford, Indiana. Some time after 

 the middle of June growing wheat was transferred from the field to a 

 breeding-cage, and aptenms, agamic females of this Toxoptera Avere 

 observed infesting tlie leaves of these plants early in July. Since that 

 time it has ai)[)eared iu wheat fields year after year in increasing 

 abundance. The species winters over in fields of fall-sown wheat, and 

 probably rye also, reproducing rapidly in the fall as long as the weather 

 remains mild, even tlumgh during the night the temperature may fall 

 considerably beh)w the freezing point. Dimng the mild winter of 

 1889-90 they were observed reproducing during mild weather through- 

 out the entire winter. During midsummer the species will live on the 

 leaves of all kinds of grain, including corn. (Jrchard grass appears to 

 suit their purpose almost as well as grain, but I did not rear them on 

 Eragrostis, Panicum, Setaria, Agrostis, Poa, or Bromus. 



' Bucktou's British Aphides, vol. 3, pp. 135,136. 

 t Ann. dclle Scieu. Xat., tie Bologna. 

 177.-i4_X,,. 7 1' 



