6 DEPARTMENT BULLETIN 1267, U. S. DEPT. OF AGRICULTURE 
leave their eggs. As the beetles themselves require a certain degree 
of moisture in their surroundings, they avoid very dry situations 
at all times. Naturally the eggs are most frequently encountered 
in places to which the beetles resort for the purpose of feed- 
ing. For this reason they are most numerous in infested corn- 
fields, and in old pastures and grassy waste lands which constitute 
the normal habitat of the species. Field observations indicate that 
cornfields, especially if they happen to be well drained and are kept 
in a good state of cultivation, are generally very unfavorable situa- 
tions for the subsequent development of the larve; for, although 
eggs are laid abundantly in corn hills, well-grown larve were rarely 
found in the same fields later in the season. This may be plausibly 
accounted for by the fact that the soil in well cultivated cornfields 
during periods of high temperature and drought is unsuitable for 
the development of the larve. 
MANNEK OF DEPOSITION 
The process of oviposition has not been observed. In most in- 
stances it appears that the eggs are deposited singly, although oc- 
casionally several may be found within a space an inch square. They 
are rarely inclosed in a clearly defined ball of earth. Possibly this 
may be due to the rather incoherent nature of the soils in which 
eggs were obtained in Virginia. At Charlottesville some experi- 
ments were conducted to ascertain whether the beetles were capable 
of forming such balls of earth by varying the moisture content of 
the soil and by adding clay to it. As a result a number of more or 
less firm balls were obtained, each inclosing a cavity containing a 
single egg (PI. Il, B, C, D, #), but the greater number of eggs were 
left loose in the soil, apparently with no attempt on the part of the 
beetles to inclose them in a ball of earth. All the earth balls obtained 
were found in soil that had been fairly well saturated with water. 
This circumstance would indicate that the particles of which the 
earth balls are composed are held together only by the cohesive 
tenacity of the clay, and not by a glutinous secretion of the beetle. 
NUMBER DEPOSITED 
The number of eggs one female is capable of depositing under 
natural conditions is difficult to ascertain directly, but some experi- 
ments conducted at Charlottesville in 1915 provide data which with 
a certain degree of reservation may be used as the basis for an esti- 
mate. These data indicate that the average deposition for each indi- 
vidual may: vary from no eggs to rather more than three a day. 
Part of this variation may be accounted for by fluctuation of tem- 
perature. It has been repeatedly observed that high temperatures 
favor deposition, while low temperatures retard it. A part of the 
variation may also be attributed to the disturbance incidental to an 
examination for eggs. 
Usually the average rate of egg production for each individual 
varies, under particular summer conditions, from 1 egg in every 4 
days to 2 eggs a day; and it has been found that a similar range of 
variation in average daily production occurs if the figures are com- 
puted on the basis of a longer period, such as a month (or its equiv-_ 
