PROCEEDINGS OF THE NATIONAL MUSEUM. 65 



The opinion has recently been advanced that the Oeophilidfe and 

 Scolopendridte should rank as orders/ the distinction being based on 

 the number of segments and spiracles. That a merely quantitative 

 difference is sufficient for ordinal distinction may well be doubted. At 

 the same time the recognition of groups of Epimori)ha higher than 

 famlHes is desirable and possible, but they can hardly be more than 

 superfamilies. Indeed, it is not easy to suggest a diagnostic structural 

 difference between the Scolopendroidfe and Geophiloidse. The two 

 superfamilies may, however, be defined as follows : 



Superfamily SCOLOPENDROID^. 



Autennte with 17-33 joints; eyes present or wanting; basal lamina 

 obsolete; iirosterual teeth present or wanting; spiracles 9-19; ventral 

 pores wanting; last pleune porose, more or less produced caudad; seg- 

 ments 21-23, constant for genera and species. 



Superfamily GEOPHILOID^. 



Antenna^ with 14 joints; eyes wanting; basal lamina present; pro- 

 sternal teeth rudimentary or wanting; spiracles present on all pedif- 

 erous segments except the first and last; ventral i)ores usually present; 

 last pleurne not i)roduced, sometimes eporose; segments 31-1^^3, not 

 constant for genera, rarely so for species. 



That future study will necessitate the recognition of family types 

 among the Scolopendroida? is not improbable; the families of Geophi- 

 loidse may be distinguished by the following artificial key: 



ANALYTICAL KEY TO THE FAMILIES OF GEOPHILOID/E. 



A. Ventral j>ores wanting; suprascutella in five rows; last pleurte occupying three 



segments Gonibkegmatid^. 



Ventral pores distinct in all cases where suprascutella are present; last pleurae 

 affecting last segment only B. 



B. Basal segment very broad, concealing the pleunc of the prehensors C. 



Basal segment not or scarcely broader than the cephalic lamina, the prehensorial 



pleur;B evident from above D. 



C. Ventral pores in one median central or posterior area E. 



Ventral pores in two or more areas, anterior and posterior F. 



D. Labrum entire; mandibles with one pectinate and 1-3 dentate lamelhe; ventral 



pores, if present, in a central area Schendylid.e. 



Labrum tripartite, mandibles without dentate lamelLne; ventral pores, if present 

 seldom in a central area G. 



E. Mandibles with one pectinate lamella; labrum tripartite, the lateral parts geatly 



reduced or rudimentary Digxathodontid.e. 



Mandibles with dentate and pectinate lamella? ; labrum entire H. 



F. Last pleura' coxseform, without pores; anal legs unarmed; anteuntu atten- 



uate 1 OUYID^. 



' Silvestri, Orders Oligostigmata and Plantastigmata, Ann. d. Museo Civico di 

 Storia Nat. di Genova, XIV, pp. 623, 634, 1895. 



Proc. N. M. 95 5 



