26 THE EARLY STAGES OF TABANID^ 



tical respiratory fissure, or the last two segments forming a respiratory tube. 

 Pupa free, without crovvn of hooks at the fore end, antennal sheaths laterally 

 exserted, parallel to the head. Betv/een them four swellings or ridges, arranged 

 in a curve and formed by chitinized folds. Above them three tubercles, forming 

 a triangle (anlage of ocelli) and behind them outwards two larger tubercles. 

 Beneath the v/ing sheaths on the inner margin of the sheath of the compound 

 eyes on each side arc two small tubercles lying one above the other. Anal seg- 

 ment with six divergent cone-shaped pointed hooks. Spiracles behind the head 

 and on the seven abdominal segments distinct and large, the former with kid- 

 ney-shaped or ear-shaped margin (Therioplectes) and often very large. The 

 pupa rests in the ground or, in some species (Therioplectes), remains in the water. 



Malloch describes the body of the larvae as "circular in transverse 

 section, elongate, tapering at both ends, and with encircling loco- 

 motor swelhngs at the segmental sutures in all genera except Goniops." 



Malloch's description of the tabanid pupa, based on the study 

 of a number of species, is the following: 



"Pupa. — Head without projecting thorns. Thoracic respiratory organs ses- 

 sile, connected subcutaneously with a large cavity on each side of median line 

 close to anterior margin of prothorax. [Plate 13, Figs. 153 and 154.] Wings 

 and legs rather short. Abdominal armature consisting of 1, or 2 closely con- 

 tiguous, series of bristles on each dorsal segment except first, and a weaker trans- 

 verse series on ventral segments; apical segment ending in six stout processes 

 which are more or less radiate and pointed. [Plate 13, Figs. 162 and 163.]" 



On the habits of the larvae before pupation, facts have been pub- 

 lished by Neave (1915). 



Before the larvae have reached their full growth, which in many 

 cases signifies the beginning of a resting period, they usually lie 

 buried in the mud, head downwards, with their syphons projecting 

 immediately above the surface of the mud or of a shallow layer of 

 water above it if it is present. In the resting stage the syphons do 

 not seem to be used and the larvae remain several inches below the 

 surface for weeks or even months. This is presumably an adapta- 

 tion connected with a climate in which there is a very marked dry 

 season, and, consequently, a risk of the mud in which they are lying 

 more or less drying up. Pupation appears to take place in normal 

 circumstances an inch or more below the surface, though occasion- 

 ally in captivity individuals pupated lying horizontally upon it. 

 The pupa is normally upright in the mud, and after pupation, as soon 



