54 TRANSACTIONS OF ROYAL SCOTTISH ARBORICULTURAL SOCIETY. 



made in a tree, but is found at the roots of conifers and broad- 

 leaved species in nurseries, as well as at the roots of grasses. 



The larva of Cetonia aurata, besides being found feeding 

 externally at the roots of plants and sometimes in the nests of 

 the ant Formica rufa, can also be found feeding in the rotten 

 wood of decaying stumps. 



The larva of Gnorimns fiobilis feeds in the stems of decaying 

 or fungus-attacked cherry trees. Gnorimus nobilis is a rare 

 beetle, but some years ago I had sent to me from Buckingham- 

 shire a section of the stem of a cherry which contained the grubs 

 of this beetle. The grubs were tunnelling in the wood which 

 had previously been attacked by fungi ; nearly twenty adults 

 were bred out from this log which was about 2 feet long. 



Different characters may be chosen in order to separate the 

 larvae (Fig. 2) from one another. Quite a good character for 

 separating the two Families is the direction of the anal slit. By 

 the aid of an ordinary hand-lens examine the hind face of the 

 last segment of the larva and note — 



1. The anal slit lies in the longitudinal direction (the Family 



Lucanidtie). 



2. The anal slit lies in the transverse direction (the Family 



Scarabaiidae). 



Schiodte divides the two Families according to the nature of 

 the stridulating organ. These Lamellicorn larvae are able to 

 make a noise, due to the rubbing of one part of the body 

 against another (stridulation) ; the parts brought into play in 

 the rubbing are known as the stridulating organs. The position 

 of the stridulating apparatus varies in the two Families, thus: — 



1. The stridulating organ is a grooved surface on the under 



side of the basal joint of the last pair of legs ; over this 

 surface there rubs a tooth-like border on the basal joint 

 of the middle pair of legs (Family Lucanidae). 



2. The stridulating organ is on the mandibles as an oval 



grooved space over which there rub teeth situated on the 

 underside of the maxillae (Family Scarabceida;). 



This distinction is a serviceable one, but the legs in the one 

 Family and the mandibles in the other should be dissected away 

 for examination under a low power of the microscope. 



Another excellent character for the separation of the larvae is 

 the nature of the upper surface of the abdomen, viz., whether 



