NOTES ON NORTH AMERICAN MYRIAPODA OF THE FAMILY 

 GEOPHILIDiE, WITH DESCRIPTIONS OF THREE GENERA. 



BY 



O. F. Cook and G. N. Collins, 



of Syracuse, N'ew Yo7-k. 

 (With Plates xxxiii-xxxv.) 



When, iu 1814, Leach erected the family GeopMlidce, he proposed but 

 the one genus, Geophilus. From that time until 1866 thirteen genera 

 were described, four by Newport, one by Gray, and eight by C. Koch. 

 The characters employed by these writers were external and extremely 

 variable, and the genera established upon them did not, "for the most 

 part, represent natural groups. The character of the work done on 

 this family previous to 1866 may be inferred from the fact that the 

 investigators were not sufficiently careful to count the legs accurately, 

 at least half the species described being credited with an even number 

 of pairs. At that date Bergsoe and Meinert published a revision of 

 the classification of the family, and among other things announced, 

 having counted the legs of some six hundred specimens, that the number 

 of pairs of legs is always uneven, and since that time writers conversant 

 with the work of these authorities have not been reporting an even 

 number of pairs of legs. Indeed, there is no well authenticatiid case 

 of a Chilopod being possessed of an even number of pairs, and Latzel * 

 remarks in his characterization of that order : 



All accounts of an even number of pairs of feet, which one can find in so many 

 works on Myriapoda, are false, and occur either through mistakes in counting or 

 through the fact that the last pair of feet has been separated from the others as anal 

 appendages, and not counted with them, which is unreasonable. 



But the writers on GeopMlidw can not be acquitted of miscounting, 

 for if the last pair were omitted the number would invariably be even, 

 while the earlier writers are continually mentioning species with both 

 odd and even numbers of pairs. 



American writers, with the exception of Mr. McNeill, have continued 

 to describe species with an even number of pairs of legs, and the last 

 paper mentioning species of this family, published during the present 

 year, mentions Eimatitarium tcvniopse as having one hundred and forty- 

 eight pairs. 



'Die Myr. d. Ost.-Ung. Monarchic, Erste Hiilfte, s. 11. 

 Pxooeedings BTational Museum, Vol. XIII— No. 837. 



383 



