"""isoo!" J PROCEEDINGS OF THE NATIONAL MUSEUM. 385 



Meinert's terminology of parts has, with very unimportant exceptions, 

 been used in the descriptions of genera and species ; not, however, with 

 any intention of implying that we can indorse all of the views of that 

 writer in regard to the development of the various organs and their 

 homologies with corresponding parts in Hexapods, in which matters he 

 antl Latzel differ so widely. But Meinert has made important contri- 

 butions to the literature of the North American species, and it would 

 seem that until these questions meet with some generally recognized 

 settlement, the convenience arising from uniformity in descriptions 

 should be a greater consideration for continuing Meinert's terms and 

 methods than any advantage to be gained by changes in accordance 

 with the momentary probability which may attach to the views of suc- 

 cessive investigators. 



While the characters drawn from the mouth parts are of most im- 

 portance, it may nevertheless be occasionally convenient to separate 

 genera without dissection. The following synoptic table is based on 

 the least variable external characters; it is a translation from the Rus- 

 sian of SseliwauofiPs " GeopMUdce museja imperatorshoi Alcademii nauk,^"* 

 so amended as to contain the new American genera. 



1. Ventral pores in definite areas 2 



not in definite areas 10 



2. Antennse short, tapering :i 



filiform 7 



3. Ventral pores in four areas Orplinwus 



one central area 4 



4. Anal lea's pseiido-seven-jointed Mesocanthm 



six-jointed 5 



5. Sterna without pronounced depressions Himantarium 



with pronounced depressions 6 



6. A deep, horse-shoe shaped depression on the anterior margin of some of the 



sterna Bothriogaster 



A deep, stigmate-like depression near lateral margin of some of the 

 sterna Stigmatogaster 



7. Anal legs five-jointed Scotophihis 



six-jointed 8 



8. Pleurae of last segment enlarged (^ 



not enlarged Chwtechelyne 



9. Spiracle-bearing scutellum adjacent to the scutum Pectiniunguis 



separated from the scutum by another scutel- 

 lum Choma tobius 



10. Ventral pores wanting 11 



present 12 



11. Claw of prehensorial feet simple at apex Esearyus 



divided at apex into three teeth Dignathodon 



12. Antennae short, tapering 13 



filiform 14 



13. Anal legs six (pseudo-seven)-jointed Orya 



five (pseudo-six)-jointed Notiphilides 



14. Claw of prehensorial feet with a large tooth at base 15 



unarmed, or with a small tooth 16 



Proc. N. M. 90 25 



