June, ’20] 
SATTERTHWAIT: HABITS OF CALENDRA PERTINAX 
293 
may have been the host plant in this case, but on May 23, the writer 
found no billbugs nor billbug work on the isolated blue flags then 
examined, while the cat-tail was very heavily infested. The two worms 
that had worked in the centers of two corn plants mentioned in Mr. 
Jenkins’ letter, were referred to Mr. George G. Ainslie for determina¬ 
tion. Under date of June 10, Mr. Ainslie reported these as Crambus 
praefectellus , a species of root web-worm usually taken singly, hence 
not usually a serious pest. There was 1 adult Diabrotica 12-punctata , 
but as none of its work was recognized on the corn leaves, it is probably 
not seriously involved. No lice, ants or gnats were found. Some of 
this shipment of corn plants were forwarded to Washington for patho¬ 
logical examination, but were spoiled before reaching their destination. 
On June 2, Dr. Cook sent to the laboratory a package containing 5 
corn plants. This package reached its destination June 6, broken 
open. No living insects remained with the corn. The partial remains 
of a male C. pertinax were found. The corn plants were crippled and 
showed punctures typical of C. pertinax adult work. The crowns also 
showed discoloration of the same type as did those from Mr. Jenkins. 
On June 9, Mr. Painter visited the “Big Field,” examining the bill- 
bug infested fields of the Messrs. Jenkins and of Dr. Cook. He agrees 
in his observations with Mr. J. H. Jenkins in the conclusion that there 
is insufficient drainage. He found the water level was within about 
8 inches of the surface of the ground and the whole area practically of 
the same level throughout. He found cat-tails quite prominent (see 
Plate 4), and cane grass (probably Arundinaria tecta (Walt.) Muhl.), 
rather plentiful, in various parts of the field. Calendra pertinax was 
abundant at this time in cat-tails. In a portion of Dr. Cook’s field, 
Mr. Painter secured 6 male and 12 female C. pertinax adults and, 
while collecting these, took 2 female C. scoparius adults, 1 on corn and 
1 on cat-tails. While this would indicate that C. pertinax represented 
only 90 per cent of the billbug infestation, the consideration of all 
adults taken by Mr. Painter where corn was growing in the “Big 
Field” on this date, 20 male and 37 female C. pertinax and 2 C. scopa¬ 
rius , the fair portion of the billbug damage chargeable to C. pertinax 
would be slightly over 96 per cent. 
In summing up the relationship of C. pertinax to the corn loss this 
year and accepting the statement of the gentlemen pecuniarily inter¬ 
ested in the corn, that the conditions we saw this year were the 
same as prevailed last year, the writer is disposed to charge C. pertinax 
with about 95 per cent of the insect damage to the growing corn plants, 
and the insect damage about 90 per cent, and direct water damage in 
some possible depressions, 10 per cent. The close proximity of water to 
the surface of the soil undoubtedly is a disadvantage to corn in this 
