24 



BRITISH ICHNiaiMONS. 



yMicrocryptus. 



for long in our catalogue as the alternate sex of C. obscurus, from which it 

 is quite distinct. The mesosulcus (sternauli) must also be examined, since 

 in coloration and the often deplanate post-petiole, the males resemble 

 certain Platylabi, and some of the females bear such facies that they are 

 separable by no other means from those of the genus Cradchneunwn {cf. 

 Ichn. Brit. i. 66). 



Tiidle of Species. 



Metathoraic spiracles large and usually d 

 Post-petiole notpunctulate ; spiracles 



elongate ( Plectocryptus, 



Tlioins. ). 

 Second segment finely punctate ; 



(J face and scutellum black i. 



Second segment glabrous ; ^ scu- 

 tellum and part of face pale. 



Anus red 2. 



Anus black. 



Orbits of $ pale ; apophyses of 9 



normal 3. 



Orbits of $ immaculate ; apophyses 



of $ stout 4. 



Post-petiole punctulate ; spiracles 



rotund-oval 5. 



Metathoracic spiracles small and sub- 

 circular (MlCROCRYPTUS, aiictt.). 

 Post-annellus not or hardly longer 



than scape ; $ flagellum dilated ; 



$ face black. 

 Metathoracic costulae entire ; meso- 



pleurae strongly punctate 6. 



Metathoracic costulae wanting or 



mesopleurae not strongly punc- 

 tate. 

 Areola entire ; terebra one-third 



length of abdomen 7. 



Areola basally incomplete ; terebra 



half length of abdomen. 

 Metanotum evenly punctate and 



deplanate; petiole of $ red 8. 



Metanotum coriaceous and convex ; 



petiole black 9. 



Post-annellus longer than scape ; 



5 flagellum filiform ; $ head 



usually pale-marked. 

 Frons closely and strongly punctate ; 



apophyses stout 10. 



Frons not closely and strongly 



punctate ; apophyses slender or 



wanting. 

 Petiolar area elongate ; frontal orbits 



of $ , and often of 9 , not black. 

 Spiracular area right-angled in- 



feriorly ; SGUtellum entirely im- 

 maculate. 

 Apophyses distinct ; frontal orbits 



white; coxae black 11. 



Apophyses wanting ; frontal orbits 



and coxae red 12. 



istinctly elongate. 



RUFIPES, Grav. 



PERSPICILLATOR, Gt'clV. 



ARROGANS, Grav. 

 FLAVOPUNCTATUS, Bridg. 

 SUBGUTTATUS, Grav. 



IMPROBUS, Grav. 



RUFONIGER, Bridg. 

 GRAMINICOLA, Grav. 



Spinolae, Grav. 

 BI FRONS, Gmel. 



abdominator, Grav. 

 ERRATOR, Marsh. 



