454 Prof. E. Brandt on the Nervous System of the 



Bihio JohanniSj L. 



clavipes^ Meig. 



albipennis, Meig. 



XYLOPHAGlDiE : Xylophagus ater^ Fabr. 



Therevid^ : Thereva nohilitata^ Fabr. 



DOLICHOPODID^ : Dolichopus popularis, Wied. 

 vulgaris^ Meig. 



The larvas of Leptidag have thirteen ganglia — two cephalic 

 (g. supra- et infraoesophageura), three thoracic, and eiglit 

 abdominal. All the ganglia are united by double connec- 

 tives, as in the imago * — a very peculiar formation, only 

 found in this family. In the other families of Dipterous 

 insects these connectives arc simple. 



The larvte of Bibionidaj, Therevidse, and XylophagidtB 

 have, like the Asilida? [Laphria atra according to L. Dufour, 

 and Laphria gilva and Asilus geniculatus according to my re- 

 searches), thirteen ganglia, occupying the whole length of the 

 body, and united by simple connectives. The nervous 

 system of the larvte of those families has two cephalic, 

 three thoracic, and eight abdominal ganglia. The first and 

 the second thoracic ganglia of the larva are near to each 

 other ; but the third thoracic ganglion is further apart from 

 the second than the latter from the first. The first two tho- 

 racic ganglia are afterwards fused, and form the first of the 

 two thoracic ganglia of the adult insect ; and the third 

 thoracic ganglion of the larva is fused with the first abdo- 

 minal ganglion, and forms the second thoracic ganglion of 

 the adult insect. 



The larvae of Dolichopodidse have thirteen ganglia, so 

 that there are two cephalic, three thoracic, and eight abdo- 

 minal ganglia. All the ganglia are united by simple 

 connectives, and occupy the whole length of the body. 

 From my resiearches on the nervous system of the Dolicho- 

 podidse (/. c.) it is known that the imago has two cephalic 

 ganglia and two ganglia in the thorax. The first thoracic 

 ganglion is formed by the fusion of the first two thoracic 

 ganglia of the larva ; and the second thoracic ganglion of the 

 adult insect is formed by the coalescence of the third thoracic 

 ganglion of the larva with all the abdominal ganglia. 



I have also examined some larvae of genera and species 

 the nervous system of which was not known till now, belong- 

 ing to the following farnilies : — 



* Ed. Brandt, " Vergl. anatom. Unters. iib. d. Nervens. d. Dipteren," 

 Horae Societ. Entom. Ross. xvi. 1879. 



