FAMILY TABANIDAE: CLASSIFICATION 273 



Although it is generally easy enough to allocate a specimen of one 

 of the commoner genera, such as Tabanus, Haematopota, or Chrysops, to 

 its proper genus, the identification of species in this 



family is often extremely difficult. The characters to Cl *f if * atio " and 

 * . . Identification 



be particularly noted are the size and shape of the 

 frontal callus, and the character of its backward extension ; the shape 

 and breadth of the front ; the structure and shape of the palpi and 

 antennae, and especially of the terminal joint of the latter. Mere exami- 

 nation of the antenna with a hand lens is apt to be misleading, as one 

 frequently finds it very difficult to determine the exact number of the 

 joints or rings, and their relative size, in this manner ; it is advisable to 

 remove the part and to clear it in potash solution, and then to mount it in 

 Canada balsam for examination under the microscope. The colouration 

 and banding of the eyes, which is often extremely characteristic, especi- 

 ally in the male, is not to be depended on as a taxonomic character, as 

 it fades rapidly after the death of the insect. It should be noted in the 

 fresh condition and recorded. 



Among the authorities on this family may be mentioned Austen, 

 Griinberg, Newstead, Ricardo and Sourcouf, in Europe ; Hine and 

 Williston in North America ; Lutz and Nieva in South America. Hine's 

 papers on the life histories and breeding of the American species are of 

 special practical value. 



The following key, to which some additions have been made, is taken 

 from Miss Ricardo's papers : 



FAMILY TABANIDAE 



A. Hind tibiae with spurs ; ocelli usually present . . . Subfamily 



Pangoninae. 



B. Hind tibiae without spurs ; ocelli absent .... Subfamily 



Tabaninae. 



A 

 SUBFAMILY PANGONINAE 



1. Third joint of antenna with eight or at least seven segments ; 



proboscis usually prolonged ......... 2 



Third joint of antenna with five segments ; proboscis short . 5ilvius, etc. 12 



2. Third joint of antenna with a tooth Dicrania. 



Third joint of antenna without a tooth 3 



3. Wings short ; body short and elliptical ..... Apocampta. 

 Wings short . . . , ' 4 



35 



