2. TABANUS 



393 



Fig. 235.. 



Tabanus glcmcopis ?. 

 X 14. 



5 (6) Large species (18 mm.). Eyes in life without any band. 



12 autumnalis. 



6 (5) Moderately large species (13-16 mm,). Eyes in life with one or 



three bands except in T. cordiger. 



7 (12) Upper black frontal callus almost linear (fig. 237) (unless rubbed) 



and connected with the lower callus. 

 Eyes in life with one band. Frontal 

 triangle light grey (unless rubbed). 



8 (9) Abdomen considerably reddish. 13 glaiicus. 



9 (8) Abdomen scarcely at all reddish. 



10 (11) Occiput very shallow, forming an almost 



linear band behind the eyes. Yellowish 

 brown species. 14 hromius. 



11 (10) Occiput distinctly puffed out behind the 



eyes. Antennae mainly ochreous. Grey- 

 ish species. 15 maculicornis. 



12 (7) Upper frontal callus quadrate or heart 



shaped, isolated (fig. 235). 



13 (14) Frontal triangle all grey. Eyes in life 



with scarcely even one band. Frons with a dark cross-band 

 level with the antennae. Antennse mainly black. 



16 cordiger. 



14 (13) Frontal triangle mainly shining black. Eyes in life with three 



bands. Antennse mainly ochreous. 17 glavcopis. 



The collector will not find the species of Tabanus (sensu stricto) much more easy 

 to name than those of TheriopJectes ; of course the two very large species are easily 

 distinguished from the rest but not from each other, and it is not easy to convey the 

 distinction between them in words. 1\ aiitmmialis is also fairly distinct, but the 

 five smaller species are easily confounded with each other and also with specimens 

 of some species of Therioplectes such as T. montanns. T. montanus is not likely to be 

 found south of Scotland and a little care will detect its hairy eyes even in the female ; 

 by far the commonest species in the south is T. bromius, though T. macuJicornis is 

 not uncommon and these two and T. glaucus are most comnionly confused ; the 

 rather yellowish brown hue of T. bromius afibrds a handy distinction and usually 

 T. maculicornis has more reddish orange antennae, while T. glaums is rather 

 larger and has the abdomen with more extensive reddish coloring ; T. cordifier is a 

 darker insect with smaller spots or flecks on the abdomen and usually all black 

 antennse, or when the third joint of the antennse is partly reddish the two basal 

 joints still remain black ; the female of T. cordiger may also be known by the broad 

 usually heart-shaped (whence its name) callus on the middle of the frontal stripe. 

 T. glaiicojns also has a broad callus on the middle of the frontal stripe of the female, 

 and may be known in both sexes by its shining frontal triangle, and it is also a 

 rather larger more yellowish brown species. 



10. T. Ibovinus Linne. Eyes bare and unicolorous, with the facets all 

 small in both sexes. Abdomen ferruginous about the base, and with only 

 one row of pale dorsal spots. Very large species. 



A very large fly, being in bulk only slightly inferior to T. 

 sudeticus, which is the bulkiest British fly. 



