5r)0 IIYMEXOPTERA. 



Gall-insects, as already stated, are often destroyed by 

 little parasites belonging to tbe fomily Chalcidid.e ; and 

 as these are liable to be mistaken for the former, especially 

 Avlien coming from the same gall, it may be well to point 

 out the tHfterence between them. The four-winced oall-flies 

 have rather long, straight, thread-like, and ascending anten- 

 na; ; the fore wings with a few veins, forming two triangular 

 meshes, one of which is very small, and situated near the 

 middle of the wing, the other mesh much larger, and near 

 the base ; the hind body roundish, but laterally compressed ; 

 and the piercer spiral or curved, and concealed. The Chal- 

 cidians have shorter, elbowed, and droo})ing antenna?, which 

 are enlarged towards the end ; a single vein, running from 

 the shoulder near the outer marijin of the fore wino;, unitino- 

 with this margin near its middle, and. emittino; thence, to- 

 wards the disk of the wing, a short oblique branch, which 

 is enlarged or forked at the end ; the hind body generally 

 oval, pointed at the end in the females, and provided in this 

 sex Avitli a straight piercer, which is more or less visible 

 l)eneath, and prominent at the extremity. By means of 

 their piercers, the Chalcidians thrust their eggs into the 

 galls made by various kinds of gall-insects, and the mag- 

 gots hatched from these eggs de^•our 

 i„ -o. . ig. ^o . ^1^^^ young of the gall-flies. (Fig. 2o4, 



larva of a Chalcidian, which attacks 

 Cynlps dicldocenis ; Fig. 255, pupa of 

 the same.) Nor do they destroy these 

 alone ; tlu-y prey upon many other 

 larva?, especially caterpillar^, and also 

 on pupce or chrysalids. Some of them are egg-parasites, 

 puncturing the eggs of other insects, and depositing therein 

 their own tiny eggs. They are the minute ichneumons 

 (^Ichneainones minuti) of Linnteus, and, like the true ich- 

 neumon-flies, they are eminently useful in checking the 

 increase of the noxious tribes. 



Such beinir the known habits and services of the greater 



