v LAMELLICORNIA SCARABAEIDAE 195 



usually leave the pygidium uncovered. The number of visible 

 ventral segments is usually six, or at the sides seven, not Jive, as in 

 Lucanidae and Passalidae. This is one of the most important 

 families of Insects. About 13,000 species are already known; 

 as some of them are highly remarkable creatures on account of 

 the males being armed with horns, they are figured in many 

 works on natural history. There is great variety of form, and 

 the following five sub-families may be adopted, though authorities 

 are by no means agreed as to the classification of this extensive 

 family, which, moreover, be it remarked, is increasing by the dis- 

 covery of about 300 new species every year. 



Abdominal spiracles placed in a line on tlie connecting membranes, and en- 

 tirely covered by the wing-cases (Laparosticti). Sub-fain. 1. CopRiDES. 1 



Abdominal spiracles placed almost in a line, but only the basal three on the 

 connecting membranes ; the terminal one usually not covered by the 

 w ing-cases. Sub-fain. 2. MELOLOXTHIDES. 



Abdominal spiracles placed in two lines, the basal three on the connecting 

 membranes, the others on the ventral segments (Pleurosticti). 



The claws of the tarsi unequal. Sub-fam. 3. RUTELIDES. 



The claws of the tarsi equal ; the front coxae transverse, but little pro- 

 minent in the descending axis. Sub-fam. 4. DYNASTIDES. 



The claws of the tarsi equal ; the front coxae more prominent, shorter 

 transversely. Sub-fam. 5. CETONIIDES. 



i. The COPRIDES form an immense group of about 5000 species ; 

 they differ somewhat in habits from other Lamellicorns, inasmuch 

 as most of them live on dung, or decaying animal matter ; the 

 sub-family connects with the Lucanidae, so far as superficial char- 

 acters go, by means of two of its groups, Trogini and Nicagini, 

 the latter being very near to the Ceratognathini in Lucanidae. 

 So little is known as to the morphology and development of 

 these groups that it is not possible to pronounce an opinion as 

 to the validity of this apparent alliance. Trox stridulates by 

 rubbing two raised lines on the penultimate dorsal segment 

 across two striate ribs on the inner face of the elytra ; Geotrupes, 

 on the other hand, produces an audible sound by rubbing together 

 a file on the posterior coxa and a fine ridge on the contiguous 

 ventral segment. The larva in this genus has a different organ 



1 In this sub-family there are numerous forms in which the elytra cover the 

 pygidium, and in which the number of conspicuous ventral segments is reduced to 

 five or even four. We use the term Coprides as equivalent to the " Laparosticti " 

 of Lacordaire (Gen. Col. iii. 1856) ; it thus includes the "Coprini" and "Glaphy- 

 rini " of the Catalogus Coleoptcrorum, vol. iv. Munich, 1869. 



