2 Proceedings of the Royal Physical Society. 
The approach even of the shadow of any creature big enough to be 
dangerous causes the larva to withdraw instantly into its hole, and it is often 
just this movement which catches the eye of the observer and betrays the 
presence of the grub. If the earth round the burrow be much disturbed or 
upheaved, as for instance by the insertion of a knife-blade, the inhabitant, 
especially if young and small, will leave in alarm and seek a securer situation ; 
where, using its mandibles for excavation and its head as a shovel, it soon 
makes itself a new “dug-out.” In arranging the inside of a burrow to its 
liking, a larva will often be head downwards, with its tail-end protruding 
from the top of the hole. A convenient way of watching operations is to fill 
a tumbler with damp sand, and make with a slender pencil a rough burrow 
close to the glass—a plan also employed by Mr F. Enoch. A fair-sized larva 
put into this hole will at once set to work, and though it will insist on 
plastering up the window as often as one may clear away the sand, still a 
good view of its methods may often be obtained. The burrow is always 
smooth-walled, and is never such a tight fit as to preclude turning movements. 
The orifice is perfectly circular with its edges smoothly rounded off. By this 
the entrances to these burrows can be distinguished from those of bee-burrows. 
which often occur in the same situation. The bee-burrows, further, slope 
inwards for some distance, while those of C. campestris } are more perpendicular 
to the surface of the soil. 
A full-grown larva measures rather under an inch in length, and its 
burrow usually exceeds three inches in depth, and rarely exceeded four in the 
district where these observations were made. The diameter of a large burrow 
at the entrance measures 5 to 6 mm. 
SPECIAL OBSERVATIONS. 
My own observations on Cicindela began in Argyllshire in July 1912. In 
the district larval burrows were numerous wherever there was a sandy, peaty 
soil open to the sun for many hours daily. They were specially common on 
old sandy dykes, and on the hillsides where cattle tracks had worn away the 
heather. The majority of the larvee were remarkably uniform in size—about 
half-grown. Fully-grown larvee were extremely rare. A peat containing five 
burrows was taken to Edinburgh for observation. At the end of August 
the larvee plugged the openings with earth and did not re-open them. 
Unfortunately, shortly afterwards, the peat was thrown away by mistake. 
In mid-July of the next year (1913) the locality was again visited. There 
were now everywhere to be found larvee with burrows 5 to 6 mm. in diameter. 
Again the uniformity in size was general. These large larve were still 
1 Other species of Crczndela show slight differences in the nature of their burrow. 
uchtullitcaes 
