72 Miscellaneova. 



his profound investigations enriched science with most important 

 facts, now well known in the scientific world. My investigations 

 upon the nervous system of the Coleoptera were made upon 235 

 species in the perfect state, and upon 36 species in the state of larvse. 

 The following are the conclusions: — 1, Some Coleoptera (RJiizo- 

 trof/ns solstiticdis) have the suboesophageal ganglion confounded with 

 the thoracic ganglion. The cerebroid ganglia always have convolu- 

 tions. 2. There are from one to three thoracic ganglia ; if there 

 are two or three, it is only the last that is composite. 3. The 

 number of abdominal ganglia is very variable, from one to 

 eight ; sometimes there are no separate abdominal ganglia, but 

 they are confounded with the thoracic part (Curculionidse, La- 

 mellicornia) ; sometimes the males have more separate ganglia 

 than the females of the same species (in Dicti/oj^terus sanguineus the 

 male has eight and tho female seven). 



My principal results on the nervous system of the Hymenoptera 

 were published in 1875 *. 



The nervous si/sti'm of the Lepidoptera had been very little 

 studiedf. I have examined it in 118 adult species, and in 48 species 

 in the caterpillar state. 1. AU Lepidoptera have two cephalic 

 ganglia ; the supracesophageal ganglion is furnished with convolu- 

 tions. 2. In most cases there are two distinct thoracic ganglionic 

 masses (Rhopalocera, Crepuscularia, and most of the other groups) ; 

 the first is simple, while the second is composite. Some have their 

 thoracic ganglia sometimes very close together (Cossus lif/niperda, 

 Pi/fjcera bucephala), sometimes distant {Zygcena, Sesia, Hepmlus) ; 

 an intermediate form also occurs (Orgyia, Notodonta, &g.), which 

 possesses two thoracic ganglia, the second having a strongly-marked 

 constriction. 3. There are always four abdominal ganglia ; Hepl- 

 alus humuli alone presents five. 



The nervous system of the Diptera was studied in several families 

 by M. Leon Dufour % ; but in most cases his descriptions are incor- 

 rect. My investigations on the nervous system of the Diptera were 

 made upon sixty-five adult species and twenty-nine species of larvae §. 

 1. The Diptera have always two cephalic ganglia, well separated 

 from each other by short commissures ; and the supracesophageal 

 ganglion always has convolutions. 2. There is sometimes a single 

 thoracic ganglion (Muscidse, Conopsidae, SyrphidaB, Stratiomydae), 

 sometimes two (Therevidae, Dolichopodidae, Xylophagidae, Bibio- 

 nidae) ; some have three thoracic ganglia (Fungicolae, Culiciformia, 

 Pulicida). When there are two thoracic ganglia, both are compo- 



* Comptes Rendus, tome Ixxxiii. pp. 612-614. 



t M. Leon Dufour is the only naturalist who has investigated repre- 

 sentatives of the different families (Comptes Rendus, tome xxxiv.). 



X ' Recherches anatomiques et physiologiques sur les Dipteres.' 



§ The principal results of my researches upon the nervous system of 

 the Diptera were read in October 1877 before the Russian Entomological 

 Society. 



