June, 1907.] 
American Species of Papirius. 
163 
there are none mentioned for any of the other species. On next 
to the last abdominal segment is an organ peculiar to the Collem- 
bola. This is known as the spring or furcula. It consists of 
four parts, as follows: attached to the abdomen is a broad, 
almost triangular piece, we may term the basal plate. This is 
covered with hairs, and forms the basal part of the spring. At¬ 
tached to the anterior border of this basal plate are a couple of 
broad flattened pieces known as the manubrium. In some gen¬ 
era these are fused, but we find them separate in Papirius 
Joined to the anterior end of the manubrium are the dentes. 
These are long and pointed and very characteristic, usually hav¬ 
ing an inner serrated edge, and numerous characteristic hairs or 
spines. At the end of the dentes we find a tooth-like structure 
known as the mucrones. These are also serrated and very char¬ 
acteristic. This entire organ is nearly as long as the body. 
On the second or third abdominal segment is an organ 
known as the catch or tenaculum. This consists of a basal por¬ 
tion and two short arms. The entire organ is small and difficult 
to see and may possibly hold the spring in position. On 
the first abdominal segment is an organ known as the ventral 
sucker. This is a short tube attached at one end and free at the 
other. From the free end may be protruded two long filaments, 
nearly as long as the body. These are covered with a large 
number of glands which secrete a sticky substance. By means 
of these filaments the insect may hold fast to smooth objects, 
or right itself, if placed on its back. 
Habitat. 
These interesting little insects may be found in numerous 
dark, shady nooks; under decayed wood and leaves in the woods; 
and always where there is some moisture, though not an excess 
of water. They remain quiet until disturbed, or exposed to a 
strong light when they prove themselves most agile in their 
movements. My experience has been to find them more on the 
under surface of chunks of decayed wood lying about in moist and 
damp situations than under bark. I have also taken them in 
numbers under stones along river banks, though never on the 
water where some of the Smynthurus are found. A most favor¬ 
able time to collect Papirius seems to be on a warm day, just 
after a little very cold weather. They seem not to have thor¬ 
oughly warmed up yet, and may be captured in vials quite 
easily by placing the vial near them and urging them on slightly 
by means of a small brush. They may be successfully bred in 
the laboratory in vials by giving them plenty of moist decayed 
wood and leaves to live on. These vials should be kept in the 
dark, giving the insects so nearly as possible their natural condi¬ 
tion. I have tried this experiment in the case of unicolor and 
