397 
126, iv). The anterior transverse vein is very oblique. 
The bend in the course of the fourth vein, before it 
meets the anterior transverse vein, is absolutely 
diagnostic. 
Fig. 12 6. Wing Venation of Glossina, and antenna with 
Feathered Arista. (After Austen) 
Life-History 
Tsetse flies are not found far from water. They 
frequent areas of thick wood or undergrowth, and are 
not found in open spaces or clearings. As a rule, 
tsetses and big game are found together, but there 
appear to be exceptions to this rule.* They have a 
great dislike for excrement of animals. 
Tsetse flies do not lay eggs, but yellow-coloured 
larvae. These have been found among the roots of 
banana trees. After a few hours these change into 
pupae. The pupa is about six mm. long and three mm. 
broad, and consists of twelve segments. The twelfth 
segment is produced into two large lips, enclosing a pit, 
the site of the respiratory stigmata in the larva. These 
lips differ in shape and size in the different pupae. At 
the anterior end is a longitudinal groove, through which 
the fly eventually emerges in about six weeks. 
Structure of the Proboscis .—The cutting mechanism 
of the proboscis is formed by the labella, the inner 
surface of which is provided with a number of fairly 
* Gl. palpalis feeds principally on crocodiles (Koch). 
