Larvce of Dipterous Insects. 455 



FuNGiCOL-iE : Sciara nigrescens^ Winnerts. 



Tiifiventris^ Macq. 



gregaria, Behling. 



Behlingn, Winn. 



Rhyphus fenestrnlis^ Scop. 



2ninctatuSj Fabr. 



LlMNOBIID^ : Tipula hdesceiis, Fabr. 



Epiphragma picta. 



Pedicia rivosa. 

 Tabanid^ : Tahamis hromius. 



The larvae of Fungicolre have thirteen or twelve ganglia. 

 Sciara has thirteen ganglia (two cephalic, three thoracic, 

 and eight abdominal). B/iyphus has twelve ganglia, two 

 cephalic, three thoracic, and seven abdominal ; and the last 

 abdominal ganglion results from a fusion of two ganglia. 



The larvffi of the Limnobiidte have thirteen ganglia, two 

 cephalic, three thoracic, and eight abdominal. The thoracic 

 ganglia are very close together ,• the ganglion infraoesophageum 

 is veiy near to the first ganglion thoracieum ; and the first 

 abdominal ganglion is very near to the third thoracic ganglion ; 

 so that these five ganglia seem to form a single thoracic ner- 

 vous mass. All the ganglia are united by simple nervous 

 cords, and are arranged along the whole length of the body. 



The larvaj of Tabanidee have only seven ganglia; and 

 there are one cephalic ganglion (ganglion supraoesophageum 

 and no ganglion infracesophageum), one thoracic ganglion, 

 and five abdominal ganglia, occupying the whole length of the 

 abdomen. The first, second, and tliird abdominal ganglia are 

 not near to one another ; but the last two are very close to- 

 gether. Some tivtie ago J. Kunckel described the nervous 

 system of the Tabanid larvse, and stated that they have 

 only two ganglia, one cephalic and one thoracic, and that 

 only in the pupa state is there disjunction of the ganglia. 

 1 do not know if it is owing to a difference of age or of the 

 species ; but the larvai of Tabanus hromius (Kiinckel does 

 not say what species he examined) have all the abdominal 

 ganglia, in the same number and similarly arranged, as in the 

 adult insect ; only the ganglion infraoesophageum is of late 

 formation (in the pupa), by a disjunction from the anterior 

 part of the single thoracic ganglion of the larva (as in Muscidge) . 

 Thus the nervous system of the larvie of the Tabanidje consti- 

 tutes an intermediate form between the nervous system of the 

 larvae of the Muscidai and the nervous system of the larvaj of 

 the Nemocera and some other families of Dipterous insects. 



