WINGLESS INSECTS. 75 



much separated. The sexual organs are quite rudimentary, only 

 the inner germigenous organs being recognisable. In aquatic 

 larvae, we find breathing tubes in the abdomen or externally "closed 

 tracheal branchiae. Towards the end of its larval existence, the 

 insect prepares for its conversion into 



b. The pupa ; it eats no more, evacuates its intestines, seeks a 

 favorable place for pupation, spins itself an envelope, digs itself a 

 hole, or conceals itself in putrefying matters, remains still for a 

 time in the larva skin, and causes this to harden; or this integu- 

 ment bursts, and the hard pupa comes forth. The form of the 

 pupa, which often allows the future animal to glimmer through it, 

 is very various; for example, the cask-like pupae of the Diptera. 

 Finally, the pupa-case is burst, and the animal comes to light 

 as 



c. The perfect insect (= imago) to take nourishment again, and 

 propagate its species. These animals are called insects with a 

 complete metamorphosis = Holometabola ; for example, the Puli- 

 cida, or fleas, (Estrida, or gad-flies, and Calypter(B=Creophilce } or 

 flesh-flies. 



The intellectual qualities of some insects stand so high, that 

 we can hardly speak of them as instinct alone. The account of 

 the development just given, like all the other general observations 

 upon insects, from Vogt, furnishes the facts for their classifica- 

 tion. 



First Sub-Class Insects without a metamorphosis 

 = AMETABOLA. 



First and only Order APTERA= Wingless Insects. 



Corpus rarissime tripartitum, plerumque abdomine et thorace 

 coalito. Caput liberum, antennis brevibus, setosis. Stemmata pluria 

 ad utrumque capitis latus, oculi veri nulli ; organa manducatoria 

 rudimentaria, suctoria aut manducatoria, maxillis acribus, mandi- 

 bulis dentatis, s&pissime sine palpis labialibus et maxillaribus ; 

 pedes aut breves, validi et unguiculati (cursorial feet), aut f/raciles, 

 longij tenueSj mobiles. Medulla abdominalis generis ; canalis intes- 

 tinalis brevis, praterea generis ; vasa urinaria 4 ad 6. Tracliearum 

 2 trunci later ales. Genii alia feminarum ; ovaria pluria, ex 4 

 aut 5 tubis composita ; oviductus brevis : sine Joculis copiilatoriis 



