34 THE CANADIAN ENTOMOLOGIST 



nearly a fifth of their length before each ganglion, with the well-developed 

 median nerves arising between them well in front of the ganglion. The last 

 two abdominal ganglia are adjoined with an indication of very short 

 connectives. 



Prionoxystiis rohinia Peck. 

 Piate II, Fig. 7. 



The connectives in the thorax are adjacent for a short distance, and those 

 in the abdomen are split for one-fourth their length in front of each ganglion. 

 There are seven abdominal ganglia, the seventh solid but composite. The 

 median system is very coarsely developed in the thorax. 



Micropterygida . 

 Plate II, Fig. 9. 



I have been able to obtain caterpillars of one species of this family through 

 the kindness of Mrs. J. D. Tothill. The larva is a miner of Spircea discolor 

 on Vancouver Island The material was collected by Mrs. Tothill and de- 

 termined by her as probably belonging to the genus Mnemonica. The cater- 

 pillars had been a long time in alcohol, and the lateral nerves could not be 

 isolated satisfactorily. The ganglia and connectives were distinct, however, 

 and are represented roughly in figure 9. The thoracic ganglia are very large 

 and the thoracic connectives are thick, rather short and completely fused through- 

 out their length, except for a median impression in front of each ganglion. 

 There were eight abdominal ganglia. So far as this evidence goes, therefore, 

 the Micropterygidae stand with the Hepialidae, forming a group very widely 

 separated from both the Frenat?e and the Trichoptera 



TricJwptera. 

 Plate II, Fig. 8. 



Only one species of this Order was available at the time; it was an un- 

 determined species belonging to the Phryganeidse. 



The ventral chain agrees closely in its most striking characters with those 

 of the Rhopalocera. The connectives of the thorax are definitely separated 

 throughout their length, giving rise to distinct lateral nerves, and there are 

 only seven abdominal ganglia. Further dissections throughout this order may 

 show very interesting conditions. 



Plate II. 

 Figs. 1 and 2. — Papilio polyxenes Fabr. Part of the ventral chain. 

 Figs. 3 and 4. — Tropcea liina L. Ventral chain of the larva, brain and sub- 



oesophageal ganglion to the second abdominal ganglion and the last. 

 Figs. 5 and 6. — Ceratomia amyntor Hbn. Ventral chain of the larva, sub- 



oesophageal ganglion to the first abdominal ganglion and the last. 

 Fig. 7. — Prionoxystus rohinicB Peck. Ventral chain of the larva, suboesophageal 



ganglion to the first abdominal ganglion, showing origins and lateral nerves 



of the thoracic segments. 

 Fig. ^.—Trichoptera. — Ventral chain of an undetermined larva belonging to 



this order. Brain and ventral chain caudad to the second abdominal 



ganglion, showing origins of median and lateral nerves. 

 Fig. 9. — MicropterygidcE. Ventral chain of a larva of the genus Mnemonica 



showing only the ganglia and connectives of the ventral chain from the 



suboesophageal to the second abdominal ganglion. 



