96 SOCIAL HABITATIONS. 
considerable interstices are left between the sticks, and in 
these spots the Sparrow loves to place its nest. Mr. F. 
Keyl has told me that he has repeatedly seen the storks 
and Sparrows thus living in amity together, the stork 
appearing to extend to a weaker bird that protection 
which it receives from mankind. 
We now pass to the Parasitic Insects. As this work 
is intended to describe dwellings which are in some way 
formed by the creatures, it is necessary to exclude all 
the parasite insects that may exist upon the animal, and 
make no habitation, such as the ticks, as well as those 
which are merely parasitic within the animal, such as the 
various entozoa. 
Of Parasitic Insects, the greater number belong to 
that group of hymenoptera which is called Ichneumonida, 
and which embraces a number of species equal to all the 
other groups of the same order. Being desirous of pro- 
ducing, as far as possible, those examples of insects which 
have not been figured, I have selected for illustration 
several specimens which are now in the British Museum, 
one or two of which have only been recently placed in 
that collection. 
The best known of all the Ichneumonide is that tiny 
creature called J/ierogaster glomeratus. 
A group of these insects and their cells is now before 
me, and will be briefly described. 
The insects themselves much resemble in general form 
the Burnet ichneumon, but are smaller, blacker, and not 
nearly so beautiful, although their wings gleam with an 
iridescence nearly as brilliant. Small as it is, this tiny 
insect is extremely valuable to us, and to the gardener is 
beyond all value, though, as a general rule, the gardener 
