388 ORDERS OP PTILOTA. 



The family Tenthredinida are termed saw-flies, from the 

 peculiar saw-like construction of their ovipositor, above 

 described ; they are vegetable feeders. The Pupivora, on the 

 contrary, are parasites, the cuckoo-flies (Ichneumonidee) being 

 eminently serviceable in checking the too great increase of 

 caterpillars and other plant-feeding insects. The Cynipidee, 

 however, or gall-flies, are vege- 

 table feeders, the females form- 

 ing galls upon various plants* 

 as above noticed. The family 

 Formiddee comprises the nu- 

 merous tribes of ants, of which 

 the A tta cephalotes, or visiting 

 ant, already figured above, the 

 Formica fusca, or brown ant, 

 Aphidi.. HO*. d,po,i,in, u. e^ in .he here figured with Polyergus 

 .i. and 2, magnified. n ^ MceiWj a rem arkable species 



which lives in small colonies, making captives and slaves of 

 the Formica fusca, may be mentioned as examples. This 





family, like all the other tribes of insects living in socu t\ . 

 through their different states consists of three kinds of indi- 

 viduals, males, females, and neuters. 



