26 



INSECTS. 



Family BRACONID^:. 



The members of this family are very similar in general appearance to those 

 of the last, though the differences in the number and form of the cells enclosed 



by the wing-nervures forms an easy distinction. In 

 habits the Braconidce are similar to the Ichneumonidce, 

 attacking as a rule the larva3 of Lepidoptera, although 

 they are found as well in those of other insects. Up- 

 wards of a thousand parasitic grubs of the genus 

 Microgaster have been taken from a single caterpillar. 

 It must be remembered that the grubs are not in reality 

 gnawing at the vitals, but are nourished by the fluids 

 circulating through the system. As an example of the 

 family, we may take the genus Microgaster, which 

 comprises many of the commonest species. The females 

 of all, except two which are parasitic on Aphides and 

 the eggs of spiders, attack the larvae of Lepidoptera, 

 especially those clothed with hair. They are themselves 

 the victims of the attacks of a species of Pteromalus — 

 a genus of Hymenoptera briefly noted above. 



Other Families. 



In the family Evaniidce the abdomen is attached 



above the middle of the metanotum, not to its lower 



Microgaster nevwrum, female (en- margin. Among these is the javelin - wasp {Foenus 



larged) ; its larva? are feeding jaculator), a species parasitical on Hymenoptera which 



atthe nata LeT ^ ^ ^ breed m old walls. In the typical genus Evania the 



species are believed to be parasitic on the cockroach, 

 depositing their eggs in the egg-capsules, and this habit will account for the presence 

 of a certain species on board ships, where cockroaches abound. The members of the 

 family Chrysididce are not easily mistaken for those of any other, being of moderate 

 size, and distinguished by the brilliancy of their colour, not only in the tropics but 

 even in temperate climates. The integuments are more or 

 less coarsely punctured, and the whole body glistens with 

 metallic lustre, golden-yellow, fiery-red, blue, and green, all 

 these being as a rule in combination. The perfect insects 

 are most numerous in the summer months, and may be 

 observed amongst flowers, on decaying timber, old walls, 

 and other suitable hunting-grounds. The females lay their 



eggs in the nest of the various burrowing Hymenoptera. It is probable that the 

 grub devours the store of food garnered for its own progeny by the careful 

 mother. Possibly it makes little distinction between the food supply and the 

 tissues of the organism nourished by them. The common ruby-tailed wasps belong 

 to this family. 



The golden burnished wasp (Stilbwm splendidum) is entirely steel-blue or 



javelin-wasp, Foenus jacula- 

 tor (nat. size). 



