﻿96 LL. LLOYD — NOTES ON GLOSSINA MOKSITANS, &C. 



only the finer twigs of the tracheal system adhering. It is now a simple matter 

 to dissect away the remainder of the thorax and head till a preparation is obtained 

 consisting of proboscis, pharynx and salivary glands. The figure shows the 

 appearance of such a preparation. The glands when first withdrawn are quite 

 transparent and exhibit an active wriggling motion. They correspond exactly 

 with the salivary glands of G. palpalis as described by Minchin." If the pull 



Fig. 1. — Preparation of salivary glands and proboscis of G. morsitans (semi-diagramatic). X 10. 

 s.g., salivary glands ; j.d., junction of salivary ducts ; oe., oesophagus ; ph., pharynx : 

 p.b., bulb of proboscis ; p.m., muscles of proboscis. 



on the fly is not perfectly longitudinal, one of the glands may break off just 

 posterior to the junction of the salivary ducts. Occasionally botli the glands 

 break away at this attenuated part of the ducts. In either event the remainder 

 of the thorax attached to the abdomen is dissected off and the protruding glands 

 are withdrawn by means of fine forceps. A little dissection of the anterior end 

 of the abdomen is sometimes necessary to effect this. 



Another method that has been adopted with some success is to draw the glands 

 out of the fly by means of the proboscis. A longitudinal median incision is made 

 in the thorax as before and the cut is opened out by means of needles with which 

 the structures in the thorax are loosened. The dorsal surface of the head, the 

 eyes and the jowls are then cut through with needles till nothing remains exter- 

 nally connecting the anterior and posterior surfaces of the head, except the thin 

 soft integument immediately behind the proboscis. The proboscis is then 

 seized with forceps and a needle is placed on the last segment of the abdomen. 

 A slow pull on the proboscis causes the glands to be withdrawn as before. This 

 method has been found to fail so frequently however that it cannot be recom- 

 mended as a working dissection. With several species of Tabanus this latter 

 method of dissecting the salivary glands has been found to be invariably successful. 



* E. A. Minchin, Proc. Roy. Soc, Ser. B., Yol. 76 ; Report on the Anatomy of the Tsetse-fly. 



