June, 1909.] Ohio Forms of the Genus Lepidocyrtus. 
527 
abdomen is long and cylindrical, the fourth segment being about 
three or four times as long as the third. The dentes are usually 
serrated, while the mucrones end in the characteristic incurved 
hook, with a middle tooth nearly as large as the terminal one. 
There may be also one or two spurs attached above these teeth. 
A tenaculum is present and lies in a. groove underneath the 
spring. 
Most of the species of this genus bear two teeth on the larger 
claw of the foot and none on the smaller. However in some 
cases, we find but a single tooth on the larger one. The irides¬ 
cent scales form a secondary character in classification, as does 
also the color of the insect, which is so dependent upon the 
reflection of light on the scales. 
Club-shaped hairs may be borne on various parts of the 
body. On the anterior edge of the mesonotum of some species 
is a characteristic collar of these club-shaped hairs, sometimes 
extending over the head for a considerable distance. Tenent 
hairs are usually present on the tibia, and very long unknobbed 
hairs are scattered over other parts of the body. Both the long 
and short hairs are often distinctly fringed. 
Geographical Distribution: —As a group, Collembola may 
be said to have a general distribution, some species covering a 
wide range. According to Folsom, Achorutes armatus has been 
recorded throughout Europe, in the United States, Uraguav, 
Valparaiso, Siberia, Sumatra and Greenland. We have no such 
record as this for Lepidocyrtus however. It has been noted 
that only the more generalized types of Collembola are found in 
very cold climates, which probably explains why Lepidocyrtus 
is restricted to the warmer regions, at least within the southern 
Arctic and Temperate zones, it being among the more specialized 
types of Collembola. They do not seem to be able to withstand 
the extreme conditions of the arctic regions but have become 
specialized to such an extent that certain special conditions of 
moisture, food and temperature are necessary for their existence. 
Again, it is probable that the somewhat restricted range of 
Lepidocyrtus is due to the fact that they have small chances for 
dispersal. Water forms one of the most important means of 
distribution that Collembola have especiallv for those forms that 
are structually adapted for a semi-aquatic life, but I know of no 
Lepidocyrtus that is thus adapted. In fact, mv experience has 
been to find them in the dryer situations, and unable to withstand 
an excess of moisture. For this reason they are not likely to be 
carried far by water. 
It is not probable that the wind can be a very important 
factor in carrying Lepidocyrtus. Their habit of secreting them¬ 
selves in the fallen wood, etc., reduces the liability of such trans^ 
