Pomona C'om.kue Joiiiwi. of Kntomoi^k-.v 853 



1)1 K IIALTKHKN DKK Dl ITKKKN 



moo I'Kl.l (JSTAKI>T 



Zfit. f. Wiss. Z(x)l. Htl. ('.. H., 1, 1!»12. 



This is a larfful anatomiial study of tlic haltcrfs of scvi-ral s|n'cio.s of 

 flit's; Snrriiphaga rannaria, ('nlliphora fri/throcfphala, Si/rphiis ballfatuti and 

 Kristalis tewox. 



The nerves poiiifr to the halteres are from the thin! thoraeie ^ariKlion, or 

 from tliat part of the fused tlioraeie eentral nervous system which wouhl 

 correspond to the third panplion. The nerve is as lar>»e or larger than the 

 other nerve which pees to the win^fs (Fipiir<' 271 ). Fijrure 271, A. is a copy 

 from the author's drawing of this or^an in Krislnlis. from the dorsal side. 

 Fipure 271, H. is from the ventral side. There an- three main repioiis, tile 

 hase, the stalk and the head. On the dorsal siiie of the lia.se are two patches 

 of sensory structures and one similar one on the ventral siJe. In the head 

 is a furrow, and on it a few .sensory hairs of the usual type. 



The author recognizes three types of sensory organs: (1) papilla', .such as 

 those at the ba.se of the organ; (2) sense hairs, such as tho.se on the head; 

 (:{) chordotonal organs. The,«e last lie under the ventral chitinous plate on 

 the l)a.s)»l part of the organ (Figure 271, H). 



The ni-rves which enter the halteres are large and seem to he entirely 

 sensory although coming off from the lower part of the thoracic ganglionic 

 ma.ss, they have a rather direct pathway through the ganglion to the con- 

 nectives which run to the suhcsophageal ganglion, as is shown in the copy of 

 tlie author's figure of a longitudinal scctimi through the ganglion ( Figure 

 271. (' and DV 



The nerve on each side divides into two upon entering the sensory 

 structure and the smaller one on the ventral side supplies some sen.se organs 

 on that side. The larger nerve is connected with sensory terminations on 

 each side (Figure 271. E). There is a chitinous mass partly separating the.se 

 two nerves. 



Of the ha.sal papilhe. the author makes two types, one sort where the 

 nerves end in slight elevations, and the kin<l wht're there arc almost no 

 elevations of the chitin. 



The chordotonal organs are similar to those found in other locations 

 among insects hut seem to he not complete enough to he organs of hearing. 

 As to the function of the papilhe and otiicr sense organs, the author is still in 

 doubt. Hy some they have been considered to be olfactory organs, but the 

 author does not favor this becau.se he thinks their structure is not enough 

 like those well known in other arthropods. lie thinks it possible that tin- 

 chordotonal organs may be for deti'cting strain and stre.ss. perhaps something 

 like a mu.scular sen.se. Similar sense organs as those found in the halten-s 

 (X'cur in the wings of insects. 



Some exj>eriments were performe<l with living tlics. When both halteres 

 were removed tin- insects were unable to fly. and if thn>wn into the air fell 



