LAMELLICOENIA. 19 



been first carried. In this case the female seems to perform the 

 whole of the parental duties, but in Geotrupes, another genus 

 common to Europe (including Britain) and India, the two parents 

 share equally the labour of constructing and provisioning the 

 subterranean nest, each species excavating a burrow of different 

 design and sometimes of great extent. In Copris, species of 

 which are found in nearly every part of the world, including 

 Britain and India, a large subterranean chamber is dug out by the 

 two beetles and provisioned. The eggs, from 2 to 7 in number, 

 in the European species which have been studied, are enclosed 

 each in a separate pear-shaped cell of complex structure, and the- 

 young, although invisible, are guarded throughout their develop- 

 ment by the mother, who repairs cracks in the cells, removes 

 mildew and probably keeps ofi' enemies. Erom the small size of the 

 families in these insects and the usual abundance of the species, it 

 must be inferred that the percentage of larval mortality is very 

 low. The cells made by some of the Indian species of Heliocopris 

 and Catharsius are very large and cased with a very thick outer 

 layer of clay, but there is always a point at which the outer 

 crust thins out, allowing sutficient air to penetrate to the interior 

 for the purpose of the inmate. 



Colonel 8ykes described in 1835 * the discovery of five of these 

 balls, which wei'e at first taken to be ancient stone cannon-balls 

 but proved on examination to contain beetle pupae. Two of them 

 were retained and the mature beetles emerged from them 1 3 and 

 16 months later respectively. These balls were two inches in 

 diameter and belonged to Heliocopris miclas, but this is not a very 

 large species and the balls of Heliocopris dominus may be twice 

 as bulky. The beetles are no doubt able to remain imprisoned 

 for considerable periods awaiting the rains which soften the hard 

 crust of their cells and allow them to escape. Mr. Lefroy records 

 that one of the balls has been found eight feet below the surface 

 of the ground. 



In a European Greotrupid, Lethrus apterus, the male has been 

 often observed guarding the burrow within which the female is at 

 work, and fiercely attacking other beetles of its species which may 

 attempt to appropriate the fruit of its labours. The burrow of 

 this species gives access to a series of oval chambers, in each of 

 which an egg is laid and a store of food provided, consisting of 

 tender shoots of the vine bitten off and carried home. 



The highest degree of social organisation of which we are yet 

 aware in these insects is reached in the PassaliDjE, the habits of 

 which have in recent years been investigated by Dr. Ohaus. 

 Although the species studied are South American, those inhabiting 

 India and most other warm regions are so very closely related 

 that the life-histories of all are probably very similar. They feed 

 upon rotten wood, and are found within or beneath old tree- 

 trunks. Within each burrow Dr. Ohaus found larvae of different 

 ages together with the two parents. This, together with the results 



* Trans. Ent. Soc. Lond. vol. i. p. 130. 



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