270 



Marvels of Insect Life. 



an obstruction. Crawshay has watched a grub manceuvring a snail for three hours 

 before it succeeded in placing it to its own satisfaction. He found that the larger 

 grubs were not so particular in this matter as the small ones. The larger snails 

 appear to know what is the meaning of this manipulation, and make an effort to 

 glide off in another direction, or twist and shake their shells from side to side. But 

 the grub has a short way with such rebels : it uses its jaws and compels the snail 

 to retreat into its shell. 



The meal lasts from eight to sixteen days, and then the grub carefully cleans 

 out the shell, using its brushes, and making many journeys to the exterior with bits 

 ol refuse. Then it rests for a time and moults its old skin. The whole process of 

 eating one snail, cleaning out the shell, resting from its labours, and changing its 

 clothes occupies a period of about forty days. It only manages to consume three or 

 four snails each summer, and always moults before leaving the empty shell. In 



the autumn it goes into hibernation in the shell it 

 has last cleaned out. For its winter rest it changes 

 its form somewhat and becomes inactive. In 

 this state it emits an offensive fluid, no doubt for 

 a protective purpose. In its active condition it 

 contents itself when molested with coiling into a 

 ring, hedgehog fashion, when its brushes of hairs 

 serve to defend it. 



The female beetle, which is so much like the 

 grub, lavs her eggs in Julv. to the number of two 

 hundred and fifty to three hundred ; but dis- 

 tributes them in batches of about thirty. They 

 are pale vellow and measure about one twenty- 

 fifth of an inch across. 



Photo M [£. Step, F.L.S. 



Snail-eating Beetle. 



The male of this remarkable little beetle is 

 shown magnified eight times. Us colour is 

 yellowish-brown and its antennae are much 

 branched. The female is quite unUke a beetle. 



Drone- Flies. 



^ of two-winged flies which 



There is a group 

 presents us with several cases of mimetic resem- 

 blance which, however, have not been quite 

 satisfactorily explained. To an earlier generation, before there was any theory 

 of protective or mimetic resemblance, the explanation was simple enough — though 

 it might not bear examination. Thus Kirby and Spence, in their Infroditcfioji to 

 Entomology,ie\\ us that " Another tribe of these little animals ... is secured from 

 harm by a different kind of imitation, and affords a beautiful instance of the wisdom 

 of Providence in adapting means to their end. Some singular larvae . . . live in the 

 nests of humble-bees, and are the offspring of a particular genus of flies {Voliicclla), 

 many of the species of which strikingly restmible those bees in shape, clothing, and 

 colour. Thus has tlie Author of nature provided that they ma\' enter these nests 

 and deposit their eggs undiscovered. Did these intruders venture themselves 

 amongst the humble-bees in a less kindred form, their lives would probably pay 

 the forfeit of their presumption." It is all very well to be called uj)()n to admire 

 the wisdom of Providence in fitting out an impostor so that it escapes the observation 



' N'olucella. 



