The Simplest Insects 
6 3 
attached to the next to last body segment or to the antepenultimate one. 
It consists of a basal part and of two terminal processes. 
It is carried bent forward under the body, with the bipartite 
tip held in a little catch on the third abdominal segment. 
In some species the catch is lacking. The springtails also 
possess a curious organ on the ventral aspect of the first 
abdominal segment which appears to be a small projecting 
sucker or tube. This sucker is often more or less divided 
into two parts, in one family consisting plainly of two 
elongate, delicate tubes (Figs. 96 and 97). The use of 
this peculiar structure has not been definitely determined. 
Some entomologists think that it serves as a clinging organ, 
enabling the insect to attach its body firmly to the object 
upon which it rests. Others believe that the sucker serves 
in some way to take up moisture, while still others be¬ 
lieve it to aid in respiration. The Collembola as well 
as the Thysanura cannot live in a dry atmosphere. 
This suborder is divided into five families, as follows 
{MacGillivray): 
A. Spring wanting. Aphorurid^e. 
lis sp., from Cali- 
B. Spring arising from ventral side of fornia. (Three 
antepenultimate abdominal segment. times natural 
PoDURimE. size.) 
BB. Spring arising from ventral side of penultimate abdom¬ 
inal segment. 
C. Abdomen elongate, cylindrical, much longer than 
broad. Entomobryid.e. 
CC. Abdomen globular, but little larger than broad. 
D. Terminal segment of antennse long, ringed. 
Smynthurid^e. 
DD. Terminal segment of the antennae short, with 
a whorl of hairs. Papiriid^e. 
Of these five families the members of one, the Aphoruridae, in which 
the spring is wanting, are non-saltatorial. In all of 
the others leaping is a characteristic habit. The 
Smynthuridae and the Papiriidas are represented by 
but one genus each, viz., Smynthurus and Papirius. 
Smynthurus hortensis is a common form in gardens, 
and may be called the “garden-flea.” It is found 
in the Eastern States in May and June “upon the Fig. 97.—The spotted 
leaves of young cabbage, turnip, cucumber, and fpringta.il, Papirius macu ~ 
J ° 0 r ’ losus, with spring extended, 
various other plants, and also on the ground. It (Natural length, 2 mm.) 
AA. Spring present. 
Fig. 96.—The spotted 
springtail, Papirius 
maculosus, with spring 
folded underneath 
body. (N a t u r a 1 
length, 2 mm.) 
