132 B. T. LOWNE OX THE PROBOSCIS OP THE FLY. 



lips ; — minute papillae, disposed in rows of from two to four, one row 

 being placed between each pair of false tracbete ; these are exactly 

 similar to those described by Dr. Braxton Hicks in the " Linnean 

 Transactions," as existing on the palpi, about the halteres of flies, and 

 in other parts of insects — only much larger. I have foimd a consider- 

 able number of precisely similar papillae just within the vulva of the 

 female fly. They are undoubtedly organs of sensation, and although 

 I have not succeeded in tracing their nerve supply at present, I do 

 not despair of doing so. 



In Mr. Topping's beautiful preparation of the fly's proboscis — 

 which I have always looked upon as a marvellous success — it will 

 be seen that the chitinous envelope is perforated for the passage of 

 these organs. I thought at first they might be ducts, and that the 

 interior of each lip contained a gland ; such could, however, hardly 

 be the case, for its internal supply of air is effected by a minute 

 branch, from the trunk supplying the maxillary muscles, which, on 

 entering the lip, divides, half running forwards and half backwards, 

 and gives off a few exceedingly minute filaments, a supply of air 

 not at all adequate to a secreting structure. 



The interior of the lips seems to be occupied by a few longitudinal 

 muscular fibres, and by a network of fibrous tissue, which supports 

 the false trachese from behind ; this is best seen by inflating the lips, 

 when it gives the interior of the organ the appearance of erectile 

 tissue ; — during life, the lips are never inflated in this manner. 



