198 THE EARLY STAGES OF TABANID^ 



in open holes in sand, where they wriggle themselves soon into the 

 desired position. Each pupa receives a label in the form of a little 

 flag which is fastened in the sand. As soon as a pupa has hatched, it 

 is taken out with its label. 



According to Neave, it is difficult to obtain good specimens from 

 bred material, as the imagos begin to fly about and to injure them- 

 selves before they are hard enough to be killed. They should there- 

 fore be placed in larger cages and kept there until they are sufficiently 

 hardened. 



Points Important in Description. — Specific differences in tabanid 

 larvse are not always easy to detect, especially in those of Hamato- 

 pota. They are generally found, according to Neave, in the distri- 

 bution of the pigmented areas on the last segment around the base 

 of the syphon and the anus. These so called pigmented areas are 

 really areas of pigmented hairs (Waterston) in which are entangled 

 small foreign bodies. Their actual color therefore varies to some 

 eictent with that of the medium in which the larvae have lived. The 

 amount of pigmentation, though not its distribution, also varies with 

 the age of the larvae. 



Hart considers the striation of the lateral areas of the prothorax of 

 great systematic importance in the description of the larvae. 



For practical purposes of description the following points should 

 be noted (Patton and Cragg): In the larvae, abdominal markings, 

 presence or absence of striae,^" characteristics of the pseudopods 

 (prolegs), length of the syphon tube, and structure of the antennae. 

 In the pupae, length of the antennal sheath, character of the thoracic 

 spiracle, particularly its inner margin, length of the hairs on the 

 abdomen, structure of the abdominal spiracles, and shape and size 

 of the spines and teeth on the eighth segment. 



Mr. James Waterston, of the Imperial British Bureau of Ento- 

 mology, is quoted by Neave as having suggested the convenient 

 name *' aster" for the group of hooks at the termination of the last 

 segment of the pupa. The form of this differs a good deal in the 

 various species, and another characteristic which seems of some 

 specific value is the nature of the uppermost section, often isolated, 



^ Especially on the thoracic segments. 



