60 GUIDE TO INSECTS. 



where it can be consumed in peace. For the young a hole is 

 excavated underground and a quantity of the food-material carried 

 down and worked into a ball, in which a single egg is laid. The 

 ball is cased with clay, which retains the moisture, and afterwards 

 serves as a cocoon. A loosely covered spot at the top admits 

 sufficient air for respiration. Some of the cells, examples of which 

 made by species of Heliocopris and Oatharsius are exhibited, are of 

 great size and weight. The two parents seem to co-operate in the 

 labour of construction, and the nest is sometimes guarded by the 

 mother during the development of the young. 



The Passalidce are found in tropical climates beneath bark or 

 within decaying wood, upon which they feed. The two parents and 

 larvae of different ages are found together, the adult beetles gnawing 

 the wood and preparing it for their young, which seem unable to 

 exist without them. The larvae are remarkable in being apparently 

 four-legged, as the hind pair of legs are extremely small and serve as 

 part of a sound -producing instrument. The claws of the hind leg 

 scrape against a microscopically ridged plate at the base of the middle 

 leg. 



The LucanidcR, or Stag-beetles, are well-known for the great 

 enlargement of the head and jaws of the males. Most of them feed 

 in rotten wood during the two or three years of larval life, but the 

 large species, Odontolabis siva, cocoons of which are shown, feeds in 

 the thatch of houses in the East, and the cocoons are made of gnawed 

 pieces of this fastened together. 



Ptinidce and Bostrichidce are exceedingly destructive to dry 

 timber, woodwork and furniture, through which their larvae tunnel 

 until rapidly succeeding generations reduce it to powder. A piece 

 of an oak rafter from the roof of Arundel Church, completely honey- 

 combed by Anobium tessellatum, is exhibited. 



A smaller species, AnoUwn domesticum, is the one generally 

 responsible for the " worm-holes " so often seen in old furniture. 

 These are the exits by which the beetles have left the wood when 

 their development was completed and their tunnellings over. 

 Anobium paniceum is also found in houses, where it attacks pro- 

 visions, and even books, boots and leather articles allowed to rest 

 long undisturbed. A small dried loaf and a book riddled by it may 

 be seen in the table-case. These beetles are the mysterious Death- 

 watches of old houses. By striking their jaws in regular time 

 against resounding wood they produce a ticking noise which in a 

 silent room is very distinct. It was no doubt more often heard in 



