ii6 



Marvels of Insect Life. 



known to all country ramblers is the oil- 

 beetle, ^ though few who are not specially 

 interested in the study of beetle life know 

 anything of its remarkable history. There 

 are numerous species of oil-beetles — we have 

 seven of them in our own country — and a 

 common species may frequenth' be seen in 

 spring dragging its bloated, blue-black body 

 across country paths. It is probably a 

 female, seeking for a favourable spot in which 

 to deposit her eggs. These she plants in 

 batches in holes in the ground ; and it is 

 calculated that her total output of eggs 

 amounts to about ten thousand. Now seeing 

 that these beetles exude an unpleasant, oil- 

 like, yellow secretion from the joints of theii" 

 legs which renders them objectionable to 

 creatures that feed upon Insects, there does 

 not at first sight appear to be any need for 

 such lavish fruitfulness. What becomes of 

 this progeny ? The oil-beetles are not 

 Insects that appear in swarms. It is esti- 

 mated that not one in a thousand of the tiny 

 grubs that issue froni these minute eggs 

 ever gets beyond the iirst larval stage. Probably, that estimate is far too high, 

 for we do not hnd the species any more plentiful to-day than they were forty 

 years ago. One may safely say that out of those ten thousand eggs there is 

 produced only one female beetle that survives to lay eggs in her turn. What 

 becomes of the nine thousand nine hundred and ninety odd will appear, and give 

 point to Tennyson's lines : — 



" Nature lends such evil dreams. 



So careful of the type she seems, 



So careless of the single life." 



The oil-beetle's eggs hatch, and, like those of the blister-beetle, give origin 



to larvai that bear little likeness to the usual types of beetle-grubs. They have six 



long legs, and are tpiite active little runners and climbers. They are long-bodied, 



but this length extends only to about one-tenth of an inch. As soon as they have 



escaped from the egg-shells and the earth they start climbing the stems of flowering 



plants and continue until they have reached the flower. Here they wait patiently 



until some other Insect visits that flower in quest of nectar or pollen. When such 



a visitor arrives the larva at once clings to its body and is carried away unnoticed. 



This form of grub is called a triungulin, because each of its six feet ends in three 



claws, and it appears to be formed solely with a view to this one indispensable 



act of its life — the clinging to a particular kind of solitary bee. But it is here 



that instinct fails it ; and in this failure we hnd the explanation of the great fecundity 



1 Meloc'. 



The Blister-Beetle. 



So called from its medicinal use in producing blisters. 

 Under the name of Spanish-fly it has also had repu-te as a 

 hair stimulant, ."^bout three-quarters of an inch in length, 

 it is of a shining bronze-green colour. Its life-history is 

 more remarkable than its uses. 



