ANATOMY OF THE GOCTT-FLY OF BAllLEY. 815- 



Tlie maxillary palps are borne by two faii-ly j^rominent 

 swellings ; their circular sense organs are surrounded by cliitiiious^ 

 rings which are incomplete antero-laterally, and two slightly 

 larger circular sense organs lie just outside the gaps in the rings. 

 The antennje are only remarkable in that the apical joint is 

 almost as broad as long, instead of being maikedly longer than 

 broad as in tbe other larva) considered hei'e. The pi^e-oral sense 

 oi'gans are inconspicuous, each consisting of two .small circvilar 

 sense organs situated close together but not carried on any specifil 

 swelling; they :iro (jui be separate from the swellings which bear 

 the maxillary palps. The labial plate is again characteristic in 

 shape, so far as the larvje considered in this paper ai-e concerned^ 

 and is remarkable in bearing two pairs of labial sense organs, the 

 anterior pair being the larger. The distribution of the small 

 cephalic sense organs is shown in the figure, except for one pair 

 which are not visil)le in a ventral view, as they are situated one on 

 each side of the head slightly dorsal to the mid-ventral line and 

 on a level with the anterior margin of the mouth-opening. 



Thoracic Sefjments. 



The chitinous denticles on the thoracic segments are considei- 

 ably larger than those on Ghlorops, They occur all round the 

 anterior margins of the first and second thoracic segments as 

 moderately broad bands. The third thoracic segment has no 

 anterior teeth ventrally and only a few laterally and dorsally ; 

 a little in front of its posterior margin, however, it bears a single 

 row of teeth extending across its A'^entral region and up most of 

 its lateral regious. Tliere are six thoracic sense organs on each 

 segment forming a transverse row behind the i'egion bearing the 

 chitinous teeth. The vestigial leg rudiments are similar to those 

 in Chloropfi. 



A hdominal Segments. 



There are nine abdominal segments, the last bearing the anus 

 ventrally and the posterior stigmatic papillae posteriorly. The 

 morphology of the last two body-segments is rather obscure, and 

 this point is dealt with below. The arrangement of the chitinous 

 teeth on abdominal segments 1 to 7 is practically identical. 

 Each bears near its anterior and posterior margin a transverse 

 band of cliitinous teeth, which are from two to four rows broad 

 ventrally, but become less numerous as they pass up the lateral 

 regions of the segment. In the first four abdominal segments 

 the teeth are continued over the dorsum as a single anterior and 

 posterior row on each segment, but on the other segments they 

 are not continued above the mid-lateral line. The posterior 

 teeth on the seventh abdominal segment form only a single row 

 ventrally. Ventiaily there is a narrow space between the 

 posterior rows of teeth of one segment and the anterior rows of 

 the next segment behind it, and this space, which corresponds 



