W. WESCHE OX SOME NEW SENSE-ORGANS IN DIPTERA. 93 



which, as I said before, Leydig. Meinert, Lowne and Kraepelin 

 consider to be taste hairs. 



As to Will's "taste cups" on the maxillae of wasps, I consider 

 them as modified taste hairs. This is obvious in the maxillae of 

 the hornet, where are found structures similar to Will's, and 

 others, more modified, showing the gradations between this and a 

 structure which is considered by Kraepelin as a " taste organ " in 

 the Muscidae (PI. 6, Figs. 4, 5). On the ligulae and paraglossae 

 of Vespa vulgaris and V. crabro I have found chitinous discs, one 

 on each part. 



In the worker of V. vulgaris there is a peculiar structure- 

 consisting of a series of papillae connected at their bases, and 

 having hollow hairs or pegs inserted at their apices (PI. G, 

 Pig. 1). These are on the basal sides of the discs, which are on 

 the extremities of the ligulae and paraglossae. In the queen - 

 wasp and the hornet the same structure is found, but on the 

 anterior side of the discs (PI. 6, Fig. 3). These are most 

 characteristic structures, and if they could be found in several 

 families and orders they might be considered as typical taste 

 organs. I think I can fulfil these conditions if the papillae are 

 separated. 



I have found a single, somewhat similar structure on the 

 maxillary palpus of A. melifica (PI. 6, Fig. 6), on the paraglossae 

 of Blatia oriental-is, cockroach (PI. 6, Fig. 9), and on the labium 

 of Panorpa communis, scorpion-fly (PI. 6, Fig. 10); these have 

 been combined with similar structures smaller in size (Figs. 7, 8). 

 If PI. 6 be examined, gradations will be found from the papilla 

 and hair on the disc in Vespa, to the very short papilla and 

 hair situated in rows between the pseudotracheae in Musca. 

 Kraepelin * distinguishes four kinds of hairs on the proboscis of 

 Musca. 



1. Ordinary hairs, which are not hollow and are not in con- 

 nection with a nerve. 



2. Hairs of touch, connected with a nerve. 



3. Glandular hairs, whose existence has been called in 

 question. 



4. Taste organs, which lie in a row between the trachea-like 

 channels, and correspond to the similar organs in the bee. 



* "Zur Anat. unci Phys. des Paissels von Musca," Zeit. fur Wiss. ZvoL, 

 1883. 



