CHAP. VII The Industries of Animals 121 



like seed. They cut off all other plants from their fields, 

 and thus their crops flourish. 



But animals store for their offspring as well as for 

 themselves. The habit is very characteristic of insects, 

 and is the more interesting because the parents in many 

 cases do not survive to see the rewards of their industry. 

 Sometimes, indeed, there is no industry, for the stores of 

 other insects may be utilised. Thus a little beetle {Sitaris 

 muralis) enters the nest of a bee (Anthophora pilifera) and 

 lays its eggs in the cells full of honey. More laudable are 

 the burying-beetles (Necrophorus), which unite in har- 

 monious labour to bury the body of a mouse or a bird, 

 which serves as a resting-place for their eggs and as a 

 larder for the larvae. The Sphex wasp makes burrows, 

 in which there are many chambers. Each chamber con- 

 tains an egg, and is also a larder, in which three or four 

 crickets or other insects, paralysed by a sting in the nervous 

 system, remain alive as fresh meat for the Sphex larva 

 when that is hatched. After the Sphex has caught and 

 stung its cricket and brought it to the burrow, it enters 

 at first alone, apparently to see if all is right within. 

 That this is thoroughly habitual is evident from Fabre's 

 experiment. While the Sphex was in the burrow, he stole 

 away the paralysed cricket, and restored it after a little ; 

 yet the wasp always reconnoitred afresh, though the trick 

 was played forty times in succession. Yet when he substi- 

 tuted an unparalysed cricket for the paralysed one, 

 the Sphex did not at once perceive what was amiss, but 

 soon awoke to the gravity of the situation, and made a 

 fierce onslaught on the recalcitrant victim. So it is not 

 wholly the slave of habit. 



4. Making of Homes, — Houssay arranges the dwellings 

 of animals in three sets — («) those which are hollowed 

 out in the earth or in wood ; (b) those which are 

 constructed of light materials often woven together ; and 

 (c) those which are built of clay or similar material. We 

 may compare these to the caves, wigwams, and buildings 

 in which men find homes. 



Burrows are simplest, but they may be complex in 



