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, CoUembola 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, Uraguay, 

 Valparaiso, vSiberia, Sumatra and Greenland. We have no such 

 record as this for Lepidocyrtus however. It has been noted 

 that only the more generalized types of CoUembola 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 CoUembola. 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 CoUembola have especially for those forms that 

 are structually adapted for a semi-aquatic life, but I know of no 

 Lepidocyrtus that is thus adapted. In fact, my 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 liabilitv of such tran§- 



