42 COLLEMBOLA OF MINNESOTA 



b. — With two long anal horns. Each post-antennal organ 

 composed of 12 to 14 tubercles. Length 2 mm. 



ambulans, 97. 

 Genus Anurophorus Nicolet 1841. 

 Anurophorus has neither post-antennal organ nor anal 

 horns. The body is slender and appears more like one of the Iso- 

 tomas in that the granular appearance common to most of the 

 Poduridse and Aphoruridce is hardly apparent. Probably our 

 species is the type species upon which the genus was founded. 



laricis, 98. 

 Genus Anurida Laboulbene 1864. 



This genus differs from the preceding in the possession of 

 a post-antennal organ. There are no anal horns. The body is 

 longer and comparatively more bulky than in Anurophorus. Our 

 species is an inhabitant of fresh water surfaces, unlike A. mar- 

 itima which occurs on the surface of some of the ocean tidepools 

 and is said to be found only on and near salt water. 



tullbergi, 99. 

 Genus Neanura MacGillivray 1893. 

 The Neanuras are sluggish, uncouth looking insects, with a 

 velvety appearance due to the granular surface. 



They may be readily recognised by their short, tapering an- 

 tennae, and broad, flat bodies. They occur in moist, rotten wood, 

 wandering around in old worm holes, or under bark or moss. 

 Some species grow to a large size, four millimetres. Our com- 

 monest species is one which is found almost all over the world. 

 Key to the Genus Neanura. 

 Dark colored, heavy, with very prominent abdominal tu- 

 bercles. A rather large species. Ocelli 6. 



muscorum, 100. 



Yellowish white, with body less noticeably tubercled. 



A small species. Two black, separated ocelli on each side 



of the head. quadrioculata, loi. 



Genus Aphoromma ]\lacGillivray 1893. 



I am in doubt as to whether this should be recognized as 



a distinct genus, as the principal character which separates it 



from Anurida is the absence of ocelli. This character alone 



would be hardly of generic importance ; yet the peculiar conical 



