T 
to require a certain amount of moisture for pupation. Of 
the same lot of larve collected and divided between two 
water-tight compartments in the same pot one watered 
and the other not, those in the watered portion pupated 
sooner and in larger numbers. ‘This experiment was 
repeated several times with the same result. The age of 
the larve in each case was unknown and the larve grown 
in the insectary were too few for purposes of the experi- 
ment but the fact that in every experiment the larger 
number pupated in the watered portion may be taken to 
indicate that sufficient quantity of moisture is an essential 
condition of pupation. 
Pupation.—When the larva is full grown, it enters the 
soil and prepares ‘usually a small chamber out of earth 
mixed with a sticky secretion. After remaining in the 
chamber for two days it moults and then turns into a 
pupa which is as naked and white as that of any borer 
beetle. (Frontispiece Fig. 4.) Larve have pupated in the 
insectary on the surface of the soil without constructing a 
chamber, but the extremely soft skin of the pupa and the 
fact that G. depressum always pupates in a mud chamber 
may be taken to indicate that pupation on the surface of 
the soil is exceptional. 
The adult beetle emerges in less than a week and is 
at first pure white, but turns brown in a couple of days 
and dull black in another day. On account of the presence 
of the minute spines already described, the body gets soon 
covered over by fine particles of earth, so that the normal 
colour gets very soon obscured. The beetles are nocturnal 
in habit. They pass the day time’in situations which are 
screened from the sun such as below bushy growths, 
round the roots of plants, and in crevices in walls. As 
soon as it gets dark, they emerge from their hiding places: 
and begin to moye about in search of food, returning to the 
shelters in the morning. In very cloudy or wet weather 
they may venture out of these even in day time. They 
are provided with glands in the neighbourhood _ of 
the anus which secrete a liquid of dark brown colour. 
When disturbed, this is exuded and spreads over the 
terminal segments of the abdomen. ‘The secretion has. 
the odour of nitric acid and probably acts as a violent 
repellant. Ants kept along with beetles stimulated to 
exude the secretion, in a test tube made frantic efforts to: 
escape and several died. 
