71 
Syrphus flies were not abundant until May 80, when they were very 
common and ovipositing. Nine-tenths of them were Syrphus ameri- 
cana Wied., and the remainder Sphewrophoria cylindrica Say. and 
Allograpta obliqua. Bassus letotorius Fab. was also quite common, 
and later almost all of the puparia of A. ob/:qua were found parasitized 
and the parasites bred from them. On June 11 no syrphus flies were 
seen, but on the 18th a third brood had appeared and were swarming 
over the field, a half dozen being seen often on a couple of feet of vines, 
and making a very audible buzz over the whole field. 
Ladybird beetles and larvee were common throughout May, but not 
until the second week of June did they become abundant. I could 
not determine any regularity of the broods of these insects. Coccv- 
~ nella 9-notata, Hippodamia convergens, H. glacialis, Megilla maculata, 
C. sanguinea, and Adalia bipunctata were all common, the first 
named being the most common. Though the larvee of these ate large 
numbers of pea lice between- June 1 and 18, they were too late to 
prevent the worst injury. . Chrysopa oculata was common, but was not 
nearly as valuable as the other predaceous insects. Altogether, the 
enemies of the lice appear too late to prevent the bulk of the injury, 
and as the ‘same was true last year, it seems impossible to place any 
dependence upon them. It seems evident, however, that the lice are 
attacked by a parasite while still in crimson clover (parasitized lice 
were also common on red clover), but are not parasitized until they 
have been on peas for some time. Is it not possible the sudden 
appearance of the lice last year may have been due to the severe win- 
ter, which killed off the parasites and other enemies which usually hold 
the lice in check on the clover and so reduce their numbers that but 
few of them spread to peas? 
The very sudden appearance of this new species last year was a 
unique entomological surprise. Where it came from was a question. 
It would seem to me that the original food plant of the pest was clover 
and probably crimson clover. It is true that crimson clover is not 
grown in the North where the louse was found destructive last year, 
but it is entirely possible that it may have spread from sections in 
which crimson clover is grown to red clover in these localities, but have 
been held in check by its parasites, and remained unnoticed. Further- 
more, the insect enemies of red clover have at various times received 
study without this species having been previously noted. On the other 
hand, there seems to be good evidence that the louse has been on crimson 
clover for several years. One of our best farmers, Mr. Frank Bancroft, 
_of Camden, Del., tells me that he has seen what he judges to be the 
same louse on crimson clover for at least six or seven years. In 1890 
crimson clover grown upon an experimental plot at the Delaware Sta- 
tion became so badly infested with a plant louse that it was feared it 
