236 SUMMARY OF CURRENT RESEARCHES RELATING TO 



larvae wliicli have not eaten chloropliyll, and is due, as Pocklington 

 has also shown, to the fine markings of the elytra and the resulting 

 interference. (2) In many forms, however, there is no metallic, but 

 only a dull colour, due to non-granular pigment in the cuticular 

 layers of the elytra. (3) The hairs may contain oily or granular 

 colouring matter, they are generally longitudinally striated, and may 

 in various ways modify the colour. The very manifold ornaments of 

 the integument are also noted. 



(b) Skeletal system. — Two difi'erent types of head are described — 

 triangular and compressed (Cantharis), and more spherical, with 

 a thickness measuring almost as much as the transverse diameter 

 {Meloe, Mijlabvum, Macrohasis). Four types of labrum with an 

 anterior margin varying from deeply concave to convex, are figured ; 

 the double nature of the epicranium is demonstrated in all the larval 

 forms observed and in many adult forms. In general, however, the 

 structure of the head resembles that of the Coleoptera generally, and 

 the description need not therefore be summarized. The antennae of 

 the males in some genera differ markedly in shape and in larger size 

 from those of the female forms. In describing the various modifica- 

 tions of the thorax M. Beauregard notes the correlative reduction of 

 the tergal arches and entothorax of Meloe, in proportion to the more 

 or less rudimentary state of the wings. 



The hitherto unrecorded structure of the elytra is described at 

 length. They are formed of two plates, united at their margins; 

 each plate consists of a cuticle and of a subjacent chitinous dermal 

 layer. With few exceptions it is only the cuticle which is coloured. 

 The free space between the superior and inferior plate is occupied by 

 hypodermic cells, and is traversed by the blood and by the tracheae. 

 From the superior plate transverse pillars pass down into the dermal 

 layer of the lower plate. They consist of a central zone continuous 

 with the cuticle, and a peripheral sheath derived from the chitinous 

 lower layer. He notes the distribution of nervures and the automatic 

 folding mechanism of the wings. In a section through a wing, where 

 traversed by a trachea, M. Beauregard distinguishes (1) a thick 

 external chitinous layer, with transverse striae, and of a more or less 

 distinct brown colour, especially exteriorly ; (2) an endothelium-like 

 layer, with ovoid nuclei regularly arranged in longitudinal rows ; 

 (3) blood, tracheae, and nerves. 



The appendages are described in detail, and special attention is 

 directed to a small accessory structure situated between the claws of 

 the tarsus, and named by Kirby and Spence the plantula. It seems 

 constant among the Meloid^, and attains in some cases a remarkable 

 development. It consists of a pale brown chitinous sac, usually of a 

 flask-like shape, with a long thin neck, terminated by one or more 

 stiff, sharp, dark-coloured hairs. The body of the flask is contained 

 within the last joint of the tarsus ; the neck protrudes between the 

 claws. In Meloe and Nemognatha it is feebly developed, atrophied, 

 and naked; in the Mylabra it is strongly developed, and covered 

 with a large number (specifically constant !) of long hairs. The other 

 Meloidie lyomoBB jjkudulie between the two extremes. M. Beauregard 



