ANNULOSA: INSECTA. 257- 



same individual, or, in other wordsj there are no hermaphro- 

 dite insects. (In some very abnormal cases amongst Bees 

 hermaphrodite individuals have been observed.) As has been 

 noticed, however, before, asexual reproduction is by no means 

 unknown amongst the Insecta, and the attendant phenomena 

 are often of extreme interest. — (See Introduction.) 



The great majority of insects, during their adult condition, 

 are terrestrial or aerial in their habits, but in many cases, even 

 of these, the larvae are aquatic. Many other insects live habit- 

 ually during all stages of their existence in fresh water. A few 

 insects inhabit salt water (either the sea itself or inland salt 

 waters) during the whole or a portion of their existence. (This 

 is the case with two or three Beetles of the families Hydrophi- 

 lidee and Dytisddce, some Hemipterous Insects, and the larvse 

 of various Diptera.) Lastly, many insects live parasitically 

 upon the bodies of Birds or Mammals, or upon other Insects. 



CHAPTER XL. 

 DIVISIONS OF. INSECTA. 



The class Inseda includes such an enormous number of species, 

 genera, and families, that it would be impossible to treat of 

 these satisfactorily otherwise than in a treatise especially de- 

 voted to Entomology. Here it will bS sufficient- to give 

 simply the differential characters of the different orders, draw- 

 ing attention occasionally to any of the more important points 

 in connection with any given family. 



As already said, the Insecta are divided into three divisions, 

 termed Ametabola, Hemimetabola, and Holometabola, according 

 as they attain the adult condition without passing through a 

 metamorphosis, or have an incomplete or complete metamor- 

 phosis. The Insects which come under the first head (viz. 

 Ametabola) are not furnished with wings in the adult condition, 

 and the three orders which compose this section are com- 

 monly grouped together under the name Aptera. By some, 

 however, this division is entirely rejected, and the three orders 

 in question are placed amongst the Hemimetabola, or even 

 grouped with the Myriapoda. 



Sub-class I. Ametabola. — Young not passing through a 

 metamorphosis, and differing from the adult in size only. Imago 

 destitute of wings; eyes simple, sometimes wanting. 



