CHIEF ENTOMOLOGICAL CLASSIFICATIONS AND SYSTEMS. 619 



1. Crustacea. (According to Cuvier, Latreille, c.) they are con- 

 tiguous to the Radiata, and especially the Echini. Upon one side they 

 join the 



2. Arachnida. (The spider-like annulosa, according to Latreille, 

 Lamarck, &c.) On the other side the Crustacea border upon the 



3. Amelabola. Insects without a metamorphosis, namely, the Myri- 

 apoda, Thysanura, and Parasita of Latreille. 



4. Haustellata. Six-legged insects with wings and suctorial mouths. 

 They join the Arachnida, metamorphose, and therefore form with the 

 following group the true insects. 



5. Mandibulata. Six-legged insects with wings and mandibulate 

 mouths. Their place is between the Haustellata and Ametabola ; the 

 latter form the transition to the fishes. 



Here, therefore, only three orders will occupy us, namely, the Ame- 

 tabola, Mandibulata, and Haustellata. 



Hitherto but three groups of the Ametabola have been found, viz., 

 the Myriapoda, which join the Crustacea ; the Thysanura and the 

 Anoplura (AnopL, Leach, Parasita, Lat.), which approach the Man- 

 dibulata. 



The division and affinities of the Mandibulata and Haustellata, 

 which are called Insecta ptilota, in contradistinction to the Ametabola, 

 as apterous insects, is represented in the following table : 



Ptilota. 

 Mandibulata. Haustellata. 



Larvae with feet, pupee obtectae. 

 Trichoptera. Lepidoptera. 



(Semblodes, Phryganea, &c.) 



Larvae apods, pupce exaratas. 

 Hymenoptera. Diptera. 



Larvse varying, pupae free and quiet. 

 Coleoptera. Aptera. 



(Suctoria, Lat.) 



Metamorphosis semi-complete, larva resembles the imago. 

 Orthoptera. Hemiptera. 



(Hemip. Hcteroplera, Lat.) 

 Larvse with six feet, metamorphosis varying. 

 Neuroptera. Homoptera. 



(Hemip., Homopt., Latr.) 



