IN THE ANIMAL KINGDOM. 105 



pupa state in a physiological sense — that which corresponds 

 in the case of the Orthoptera and Hemiptera, is the later 

 period of development within the egg. In other words, 

 these embryos pass through stages, corresponding both to 

 larva and pupa within the egg, or at least are only dis- 

 charged while still undergoing some of the concluding 

 changes of the latter state. Mr. Andrew Murray brings for- 

 ward evidence to show that in some cases even a sort of 

 cocoon is formed within the egg, and that the young insect, 

 after certain changes, emerges from it, before it is finally 

 discharged from the egg.* 



In the lower orders of Insects, the development is more 

 or less arrested ; in the Anoplura, and Thysanura, which 

 come out of the egg as active pupae, there is no farther 

 metamorphosis, and in the Homoptera, it is so far imperfect 

 that but two wings are formed ; in the flea tribe also, 

 though the larva and pupa states are regularly gone 

 through, the development of the imago form is imperfect, 

 the abdomen not being marked off from the thorax, and the 

 wings being represented only by rudimentary appendages 

 attached to the second and third segments of the body ; in 

 Diptera the posterior wings are in like manner rudimentary. 

 In other cases it is only one of the sexes, or it may be only 

 certain individuals of the sex, whose development is so ar- 

 rested. Thus the females of Coccus and Lamj^yris never 

 develope wings, and in the ant tribe neither these organs 

 nor those of reproduction are evolved in the majority of the 

 sex, full development being attained by a few individuals 

 only, which breed for the whole community. Among the 

 Termites, or white ants, the '' soldiers" appear to be pupiie 

 arrested in their development, while the " workers" have 

 the characters of permanent larvae. The working females 

 of the bee, on the other hand, acquire the external charac- 



* Ed. Phil. Journal. 1S58. 



F 3 



