180 



INVEKTEREATE ANIMALS. 



duced ill great numbers at ])articiilar times of tlie year. They then 

 ciuit the nest and pair, after wliicli tlie fecundated females lose their 

 wings and form fresh societies. The workers (fig. 125, h) are some- 

 times all of one kind, but they are often divided into two, or even 

 three, distinct classes or " castes." The Ants exhibit many most 

 extraordinary and interesting instincts and haljits, of which their 

 custom of "milking" the little Plant-lice has been already men- 

 tioned. Another very singular habit of some Ants may be just 

 alluded to — their habit, namely, nf capturing the pupie of other 

 species of Aiits and bringing them up as slaves. The relations, 

 however, between the masters ami slaves vary a good deal in dif- 

 feicnt cases. In the case, for instance, of the E.usset Ant (Formica 

 nifesrnix) the masters are so entirely deiiendent u]ion their slaves 

 that tliey cannot even feed themselves, and the only work which 

 they jierform unassisted is the ca,ptnring of fresh slaves. In the 

 Blood-red Ant (Furniira .iiiin/iiiiifii\ on the other hand, the slaves 

 are much fewer in number, and the masters are much less dependent 

 ujion their good offices. In all case-;, the slaves exhil;)it the greatest 

 devotion to their masters, and are invariably taken the greatest care 

 of by their cajitors. 



Order X 1 1. Strkpsiptera. 



This is an extremely sm.-ill ordei' of insects, whicii merely requires 

 to Ije mentioned. It includes only cei'tain miiuite parasites, which 

 are found on bees and other I/i/meiwptcni. The fenrales are desti- 



Fi;,'. Hill.— .St.n>psi|ilPr.i. Sliihip.^ Spnir:! i, gnatly Tiingiiilii il (iifli'i- Westivoml). 



tide of wings or feet, and ,'irc merely soft worm-like grubs. The 

 io:i,les (fig. l^(i; are active, and |iosscss a single pair of large mem- 

 bi,iiM,us wings. Unlike the Diplini, it is t\\e posterior jKiir of wings 

 whirli tA jjrusent, and the :iiit< rinr pair is quite rudimentary, and is 



