245 
relation, in that the parasites generally issue from one to three weeks 
before the eggs hatch, or would have hatched. In Missouri, in 1870, 
parasites issued May 9 and young Mantids May 14. In Washing- 
ton, D. C., in 1881, parasites issued May 12 and young Mantids May 
21. In California, in 1888, parasites issued in March from an egg mass 
received from Japan, while the young Mantids made their appearance 
April 16. The present year parasites issued in April from egg masses 
received from Arizona, from which the young Mantids issued May 18. 
NOTES ON THE GRAIN TOXOPTERA. 
( Toxoptera graminum, Rond.) 
By F. M. WEBSTER. 
This is a grain-affecting Aphidid which the U.S. Entomologist has 
peen studying for some years. Though of foreign origin, without much 
doubt, it has probably been a constant inhabitant 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 
much greater numbers. Buckton* 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 appeared in that country. 
That the species at times becomes exceedingly abundant is indicated by 
Rondani’s account of its appearance in 1853 “in the streets of Bologna 
in innumerable swarms, to the annoyance of the inhabitants.” t 
My ownacquaintance with the species began early in July, 1884, while 
studying the habits of Isosoma, at Oxford, Indiana. Some time after 
the middle of June growing wheat was transferred from the field to a 
breeding-cage, and apterous, agamic females of this Toxoptera were 
observed infesting the leaves of these plants early in July. Since that 
time it has appeared in 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 though during the night the temperature may fall 
considerably below the freezing point. During 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. Orchard 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. 
*Buckton’s British Aphides, vol. 3, pp. 135,136. 
t Ann. delle Scien. Nat., de Bologna. 
17754—No. 7 2 
