OF THE INTELLIGENCE AND OF INSTINCT. 161 



allied to the wasp, live, when adult on vegetable food, 

 as larvse on animal substances. They thus provide for the 

 young a food they do not themselves use ; they place near 

 the nest the body of a spider or of some caterpillar, which 

 they have pierced with their sting. The xylocopes (Fig. 105) 

 have similar habits, and hollow out in timber a series of 

 cells, serving at once as nests and storehouses for their larvae. 



Fig. 105. Xylocope (Carpenter Bee). 



Fig. 106. Nest of the Xylocope. 



328. The adult bird seldom provides any nest or 

 dwelling for itself ; it is for its feeble and tender young that 

 it labours with such skill and perseverance in the construction 

 of a dwelling for them when they most require it. These 

 nests, which vary with the species, are yet as it were identical 

 as regards any species, and are uniformly constructed in the 

 way best befitting the young of that species. They vary in 

 their position, in forms, and composition, but most have 

 a hemispheric form, the exterior formed of stalks and grass 

 and herbs, the interior of soft downy substances, as moss 

 (Fig. 107) ; but at times they are more complex. A well- 

 known instance is that of the baya of India, a bird of the 

 nature of our bullfinch ; the nest it forms resembles a bottle, 

 and is suspended to the branch of a tree, so that neither apes, 

 serpent?, nor even squirrels can reach it ; the entrance to the 

 nest, moreover, looks downwards, so that the bird can only 

 enter from below, and flying. It has two chambers, one for 

 the male, the other for the female. Another nest equally 

 curious is that of the Sylvia sutoria, which converts the cotton 



