[September 



of the female Xylehovus dispar is cylindrical, that of the male becomes 

 globular. The thorax in the males of the genus Lamophlcpus are 

 much more narrowed behind than in the other sex ; that of the male 

 Nacevdes inelaniLva is so much narrowed behind as to become heart- 

 shaped, while the female has this portion quadrangular; an opposite 

 condition obtains in Eros aurora, in which the male thorax is narrowed 

 towards the front. The genus Silis is at once recognised by the sides 

 of the male thorax being excised and furnished with a tooth. The 

 surface of the thorax of the male Hydroclms exsculptiis is convex with 

 only two distinct depressions ; that of the female is much flatter and 

 has four deep depressions. That of the male stag beetle fLucanus) is 

 flatter and so finely pubescent as to look mealy, while the female has 

 this portion of the body, like the rest of the surface, more convex, 

 shining, and destitute of pubescence. Several of the smaller 

 Brachelytra such as Ilobates nigricollis, Myrmidonia fimesta, humeralisy 

 &c., Homalota divisa, and Tachyusa ohsciira have the thorax 

 longitudinally channelled in the male, while the female is either 

 without or with a much less distinct channel. A similar condition 

 happens in the males of Melasis bnprestoides, where the thorax 

 is channelled for its whole length ; in the female the groove only 

 exists at the base. The males of several of the ApJiodii (josser, 

 jimitavins, and foetens), have a round depression occupying the front 

 of the thorax, which is quite absent in the females. In this genus, 

 too, the male thorax tends to be broader and more parallel sided, 

 while that of the female is more regularly rounded to the front. In 

 the females, but not in the males of RJiynchites hetulcB, papuli and 

 (innitus the thorax is furnished on each side in front with a long 

 spine. The male Typhaus viili^nns lias three long horns projecting 

 forwards, one from each anterior angle and one from the middle of 

 th-^ front, whi]e the female has simply two little tubercles or a ridge 

 in front. The males of Blediiis spertabilis, tricc/ULS and tcnicornis, in 

 addition to possessing iicrns springing from the head also have a long 

 iiorn projecting over the head from the middle of the front of the 

 thorax ; the females have the thorax unarmed. In the male of 

 Cis hilaDicllatus the front margin of the thorax is raised in the form of 

 a plate, v/hicli with a similar plate on the head leads to its specific 

 name. Emicartlii on fronticorne has the front of the thorax cut out, 

 with a tubercle or blunt horn on each side of the notch, while £. 

 cornutiun has a sharp horn on each side. In the males of Sinodendron 

 the front angles of the thorax are very sharp and prominent, and a 

 depression in the front ib bounded behind Sy a ridge cut into three 

 conical teeth, so that the thorax appears 5-toothed — a condition 

 wliich is not present m the female ; while in the male of Copvis 

 liniavis iha thorax is deeply hollowed on each side in front with an 



