27 2 TRANSFORMATIONS OF INSECTS. 
appear in the month of April, but the greatest numbers fly in the 
month of May; towards the end of June they are almost all gone. 
They eat the leaves of many trees — such as the oak, the beeches, 
the maples, and the poplars, and sometimes the elms. Occa- 
sionally the trees are completely spoiled and killed by the May 
bags. They are almost nocturnal in their habits ; they dislike the 
sunshine, and seek the shade during the day under the branches 
of bushy trees. They wake up in the morning, and are moderately 
lively then ; but during the evening they are particularly active, 
and fly here and there, making a sonorous buzzing noise. They 
are heavy and very clumsy in their flight, as most of us know, for 
when we are walking out in the warm spring evenings there is 
often some difficulty in escaping these dull and stupid-looking 
beetles ; in fact, they prefer banging against everything, rather 
than guiding themselves away from obstacles which are hard 
enough to do them injury. 
The May bugs do much mischief when they are beetles, but 
the ravages they commit in the larva state are of most serious 
consequence to agriculturalists. The female beetles dig into 
decaying matter, or light soils, and hide themselves whilst they 
lay about forty eggs. The larvae are hatched at the end of four or 
five weeks, and by this time the tender vegetation of early summer 
is progressing rapidly. Then these white worms or cockchafer 
grubs, as they are often called, find themselves surrounded by 
abundance of food, and, unfortunately, of that kind which is very 
precious to man. They do not eat the leaves, but the delicate 
roots which come in their way as they crawl underground ; and 
thus a vast number of plants is destroyed. The larvae grow very 
slowly, and do not undergo any metamorphosis until their third 
year ; and then they are transformed into nymphs during the 
months of March or April. Some weeks afterwards the beetles 
escape and fly. The long duration of their growth and evolution 
explains how it is that these beetles usually visit us in great 
numbers every third year ; but it would appear that unusual heat, 
or seasons of great cold, have something to do with the accelera- 
tion or retardation of their development. It is not uncommon for 
larvae to undergo their metamorphosis towards the end of their 
second year, when the summer has been unusually hot ; but even 
