126 THE ENTOMOLOGIST. 



Stenobothrus biguttulus (Linn.). — This species, with the 

 common English S. bicolor (Charp.), form a group of Steno- 

 bothrus quite distinct from all the other species of the genus. 

 This is Brunner's fourth group, characterised by the dilated 

 mediastinal area of the elytra and the sharply angled ridges of 

 the pronotum. 



Charpentier * was the first to recognize the distinction be- 

 tween the two species, but they were united as one by Fieber 

 and by Fischer. Excepting Philippi, t de Selys Longchamps, \ 

 and Brisout, § all authors regarded them as one, until Brunner 

 carefully distinguished them in his invaluable ' Prodromus der 

 Europaischen Orthopteren.' Orthopterists have since followed 

 Brunner, and we owe to Krauss || an excellent essay on the two 

 species. 



In his first work on French Orthoptera, Finot 11 allows him- 

 self to say that "II m'est impossible de faire la separation d'une 

 maniere certaine," but in his later and more comprehensive 

 book ** he distinguishes them after Brunner. 



The difference between the two species lies in the venation 

 of the elytra. 



In his synoptical table of the genus Brunner gives the 

 following points of separation : — 



6. Area externomedia elytrovum hand ampliata, venis radialibus 

 rectissiinis. Area scapulari elytrorum vena longitudinali spuria 

 instructa, venulis transversis rectis ..... bicolor. 



6. 6. Area externomedia ampliata, venis radialibus prima et 

 secunda subfiexuosis. Area scapulari el. vena spuria nulla, venulis 

 transversis valde flexuosis ...... biguttulus. 



These points are subtle enough, but with a hand lens are 

 quite distinct. In the male biguttulus, the anterior radial, as I 

 prefer to call Brunner's externomedial area, is far more strongly 

 arched than in bicolor ; the actual marginal vein is stronger and 

 thicker. In biguttulus the first and second radial veins are wavy, 

 whereas they are quite straight in bicolor. 



The females are somewhat more difficult. In biguttulus the 

 scapular area has no extra, adventitious or spurious vein, and 

 the small cross veins are distinctly wavy ; in the female bicolor 

 the scapular area is furnished with a small spurious vein running 

 parallel with the radial veins, and the small transverse veins 

 are straight. 



* ' Horae Entomologies,' 1825, 161. 



f Orth. Bero). 1830, 36, tab. ii. fig. 6. 



| Ann. Soc. Ent. Belg. vi. 51 ; xi. 31. 



§ In Yersin, " Extraits d'une lettre adressee a M. L. Brisout sur les 

 Orthopteres d'Hyeres," Ann. Soc. Ent. France (3), iv. 1856, 48, note. 



|| Verb. z.-b. Ges. Wien, 1886, xxxvi. 141, tab. v. figs. 4 and 5. 

 11 Orth. de la France, 1883, 60. 

 :;::;: Faune de la France, Ins. Orth. 



