APPENDIX 203 



Order 6. Hemiptera. Bugs. Insects with two pairs of wings, or 

 wingless, with sucking mouth-parts in form of a jointed proboscis, 

 and incomplete metamorphosis. Ex. Aphis. 



Order 7. Lepidoptera. Butterflies and moths. Insects with two 

 pairs of scale-covered wings, sucking mouth-parts in form of a long, 

 un jointed proboscis, and complete metamorphosis. Ex. Bombyx. 



Order 8. Diptera. Insects with one pair of wings, sucking mouth- 

 parts, and complete metamorphosis. Ex. House fly. 



Order 9. Hymenoptera. Insects with two pairs of wings, biting 

 and licking mouth-parts, and complete metamorphosis. Ex. Bee. 



PHYLUM VI. MOLLUSCA 



Animals without paired locomotory appendages, and with a soft, 

 unsegmented body, which is usually enclosed in a calcareous shell. 



Class 1. Amphineura. Symmetrical mollusks without a shell or 

 with one composed of eight pieces in a longitudinal row. Ex. 

 Chiton. 



Class 2. Scaphopoda. Symmetrical mollusks with a cylindrical 

 shell. Ex. Dentalium. 



Class 3. Gastropoda. Snails. Mollusks with an asymmetrical, spiral 

 shell and a single mantle cavity. 



Order 1. Opisthobranchiata. Marine snails with posterior gills. 

 Ex. Aeolis. 



Order 2. Pulmonata. Freshwater and land snails, without gills 

 but with lungs. Ex. Helix. 



Order 3. Prosobranchiata. Mostly marine snails with anterior 

 gills. Ex. Fulgur. 



Class 4. Pelecypoda. Symmetrical mollusks with a bivalve shell 

 and paired mantle cavities. Ex. Unio. 



Class 5. Cephalopoda. Mollusks with a large head, which bears a 

 number of long arms, and with a single mantle cavity. 



Order 1. Tetrabranchiata. Cephalopods with four gills and a 

 large convoluted- shell. Ex. Nautilus. 



Order 2. Dibranchiata. Cephalopods with two gills and either 

 eight or ten arms ; shell, when present, concealed in the mantle. 

 Ex. Loligo. 



