70 



PROCEEDINGS OF THE ACADEMY OF 



[Feb. 



THE FRONS IN BEMBIDITJM, WITH DESCRIPTIONS OF NEW SPECIES. 

 15Y F. E. JJLAISDELL, M.D. 



There is often connected with the recognition and placing of 

 species in the systematic scheme difficuhies whicli become perplexing 

 and annoying, not so mnch from the nature of the characters as 

 from the instability or tendency to variation in such characters 

 among species naturally closely allied. 



I was forcibly impressed by these facts while working over the 

 species of Bembidium contained in the collections of Mr. Charles 

 Fuchs, Dr. E. C. Van Dyke, and my own. It is the perplexities 

 that arose while dealing with the frontal characters that have 

 brought about this attempt at their elucidation. I wish to express 

 my thanks to the above-mentioned gentlemen for the use of material 



and also for many sug- 

 gestions. 



That part of the 

 cephalic exoskeleton 

 constituting the inter- 

 ocular region is called 

 the fi'ons. It^is bounded 

 above by the vertex, 

 from which it is sepa- 

 rated by an imaginary 

 line ; below by the epis- 

 toma, with which it is 

 connate, the line of 

 union being marked by 

 the frontal suture; lat- 

 erally by the eyes, in 

 front of which is a 

 strong chitinized plate 

 supi)orting the anten- 

 nre. The union of this 

 plate with the side of 

 iiitui ridue. 



Head of Bembidium suspec.ium. — 1. Lab- 

 rum ; 2. Epistoma ; 3. Frous ; 4. Vertex ; 5. 

 Frontal sulcus (internal of Hay ward); 6. 

 Frontal costa or ridge ; 7. Anterior supra- 

 orbital setigerous puncture within fovea ; 8. 

 Posterior supraorbital setigerous puncture, 

 fovea not developed ; 9. Eye ; 10. Plate in 

 front of eye; 11. Ocular bead, ocular sulcus 

 just within ; 12. Basal joint of antenna ; 13. 

 Anterior lateral process of frons ; 14. Frontal 

 suture ; 15. Mandibular scrobe, bearing a 

 seta arisin,^ from a puncture. (Magnified 28.5 

 diameters.) 



the frons in front of the evo forms tlic fr 



