ee 
29 
remained for three days in this contracted and curved position, and 
this is probably about the usual warm weather quiescent period before 
assuming the pupal condition. 
Shimer states that the insect ‘‘remains in the pupa state about two 
weeks.” This period will, of course, vary with climate and season. 
Experiment with a number of individuals early in August showed this 
period to be seven days in moderately cool weather (75° to 85° F.), 
The pupa during normal midsummer weather remains entirely white 
until the fourth-day, but on the fourth day before transforming to 
beetle the eyes take on a light-brownish hue; on the third day this 
becomes dark brown, and on the second ge eyes turn nearly black. 
On this second day also the tips of the mandibles acquire a reddish 
hue. Even just before transformation to beetle there are comparatively 
few changes, and the beetle itself when first transformed is mostly 
white, the thorax showing yellowish, and only the eyes, antenne, mouth- 
parts, and knees and tarsi of the legs, showing infuscated. 
Transformation to pupa takes place in a fairly well-defined pupa 
case in the earth, in which the insect has been living as larva. 
One beetle was observed just transformed from pupa at 8 in the 
- morning, but early on the following morning, it was found, although not 
fully colored, to be quite active. 
The dates of earliest appearance and disappearance of an insect are 
often difficult of ascertainment. The present species appears in the 
vicinity of Washington some time in April, and was last seen the second 
week of October. In ordinary weather the beetles probably remain 
in the field considerably later, but it rained almost continuously for the 
next three weeks after this last observation and no beetles could be 
found November 6. 
The beetles of this species have a habit of hiding under clods of earth 
and other places of concealment. Toward the end of August beetles 
were seen to congregate in numbers under the stems, prostrate por- 
tions of the plants and withered leaves of cucurbits, often as many as 
fifty or sixty individuals having been counted about a single plant, 
and later they massed themselves upon such belated melons and other 
cucurbit fruit as could be found, as previously narrated. 
The entire life cycle of this insect has evidently never been ascer- 
tained. Considering its long season, and the fact that newly trans- 
formed beetles have been observed from the second week of July till 
_the first week of October, it is safe to assume the existence of at least 
three, and perhaps four, generations annually for the latitude of the 
District. 
A dipterous parasite of this species has been very abundant the 
present season. It is found only in the adult beetles and has been 
reared from July to September in this latitude. This parasite, now 
referred to Celatoria diabroticw, was first observed by Shimer in 1870 
preying upon Diabrotica vittata Fab., and an account of it was given 
