116 
on the roots, or sometimes on the fruit and vines as they lie upon 
the ground. The length of the larval period no doubt varies 
greatly, depending on the food supply and climatic conditions. 
The pupa (Fig. 9, c) is formed in an earthen cell in the soil, and 
the transformation to the adult beetle is completed within 7 to 14 
days. Altho the beetles of this new generation begin to emerge 
the latter part of July, they may continue to appear thruout August. 
Professor Garman, in his studies of this insect.* found that in con- 
Fig. 10. Striped Cucuaiber-bettle, Diubrotica vittala, egg, much 
enlarged, with portion of surface more highly magnified at 
right. 
finement the entire life cycle of an individual was 26 to 33 days. 
It is possible that a second generation may appear in the southern 
part of the state, but in northern Illinois probably but one full 
generation occurs under normal conditions. 
Preventive and Remedial Measures. — A large number and 
variety of methods for the control of this insect have been recom- 
mended, but only those which have given promising results will be 
discussed. One of the oldest methods for protecting the young 
plants from the cucumber-beetle is covering them with a screen : 
but while this is very satisfactory in small gardens, it is not so 
practicable on a large scale as the use of the Bordeaux mixture in 
connection with a trap crop, as discussed farther on. It has been 
found that for a short time in spring, before the beetles begin to 
pair, they may be killed with a spray of Paris green or arsenate of 
lead, but that they will not feed readily upon sprayed foliage after 
pairing, and arsenicals alone can not be generally recommended 
for the cucumber-beetle Avithout further tests of their efficiency. 
The use of squash as a trap crop (Fig. 11) in combination with 
a spray of Bordeaux mixture or Bordeaux and arsenate of lead 
on the cucumber plants and an arsenical poison on the squash, is 
one of the best means of preventing the attacks of these beetles. 
Mr. F. A. Sirrine has given a very complete account of this method 
of treatment based on his own experiments, and the following is 
taken largely from his paper.f 
Squash seed is planted around the margin of the field about four 
days previous to planting it with cucumbers, or other crop.+ At 
*Enemies of Cucumbers and Related Plants. Bull. Ky. Agr. E.xper. Station, 
No. 91 (March 8, 1901), p. 5. Lexington. 
tCombating the Striped Beetle on Cucumbers. Bull. N. Y. .\gr. E.xper. 
Station, No. 158 (May, 1899), pp. 14-16. Geneva. 
tMr. Sirrine informs us that only the Hubbard or the Boston Marrow squash 
should be used, these being by far the most attractive to the beetles. 
