1906.] , 1-31 



my Table a few more of which I have not seeji British specimens, but 

 which appear to be ilescribed from native insects by Mr. Cameron. 

 These in my Table following I mark thus f. 



SYNOPTIC TABLE OF BRITISH PTERONUts spp. 



1. Stigma black or dark brown '^* 



— Stigma pale (white, green, yellow, or, especially in some J <? , faintly infuscated 



but not really dark) ^• 



2. Abdomen entirely orange-yellow in both sexes. Antennae, costa, and stigma all 



black. Saw-sheath of ? (viewed from above) broadly rounded, not tapering, 



at its apex. A large species (7— 10 mill, long) salicis.Jj. 



~ Abdomen never entirely yellow in the ^ ; seldom so in the 9 , and then with the 

 saw-sheath tapering lo a narrow apex 3* 



3. Costa bright yellow, contrasting strongly with the dark stigma. Antennae black. 



? Abdomen yellow, with a tapering saw-sheath f dimidiatus, Lep. 



= melanovephalus, C. 



— Costa as well as stigma dark ^^ 



4. Vertical area (i. e., the oblong space between ocelli and occiput) at most twice as 



broad as long. Antennae more or less pale, at least beneath. Abdomen 

 orange, generally with black transverse markings above. (One of our com- 

 monest species) ••.•. W6e.su, Scop. 



— Yertical area quite thrice as broad as long. Antennae generally quite black... 



leucotrochus, Htg. 

 (? coUinus, ? consobrinus, C). 



5. Anteiniae black 



— Antennae at least partly pale ^'^• 



6. Frontal ridge (t. e., the transverse elevation situate about half way between the 



anterior ocellus and the insertions of the antennae) interrupted in its centre 

 by a deep groove. 



The ? abdomen is orange, with a square black mark at its base sur- 

 rounding the " blotch " pavidus,Lep. 



— Frontal ridge continuous, unbroken '' 



7. Abdomen entirely black above (only the venter pale). Head narrowed behind 



the eyes. Clypeus pale whitish-yellow ffuscomaculatus, Forst. 



{strongylogaster, C). 



— Abdomen above only black centrally, its sides, as well as the venter, pale 



, 8. 



or red 



8. Large species (6-8 mill. long.). Abdomen above broadly black, its sides and 



venter dark brick-red. Clypeus red. Long, heavy-looking antenna. Head 



thick and broad behind nigricornis,J.e^. 



{zetterstedti, C). 



— Smaller species. Head more narrowed behind the eyes. Colour paler, light 



reddish-yellow, or greenish, or ochreous ^' 



