526 CLASS viu. 



Campylus FISCH., ExopJithalmus LATH. Head behind the eyes 

 exsert from thorax. Eyes large, globose. Body elongate, almost 

 linear. 



Sp. Campylus linearis, Slater linearis L. (and Slater mesomelus ejusd.), 

 PANZER Deutschl. Ins. Heft 8, Tab. n. 



Elater nob. Head received in thorax as far as the posterior 

 margin of the eyes. 



Sub-genera: Ludius LATH., Ctenicerus LATR., and many others proposed 

 by ESCHSCHOLTZ and STEPHENS. Comp. WESTWOOD Modern Classific., 

 Generic Synopsis, pp. 25 27, and GERMAR Zeitschr. f. die Entom. n. 

 pp. 241278, iv. pp. 43 108, v. pp. 133192, &c. 



Sp. Elater murinus L., VOET Col. I. Tab. 44, fig. 26; Elat. ceneus L., 

 VOET ibid. fig. 24 ; Elater aterrimus L., PANZER Deutschl. Ins. Heft 101, Tab. 

 15, &c. The larvae of Slater (Agriotes ESCHSCH.) segetis, Elater lineatus L., 

 and other similarly thin and elongated species are sometimes extremely 

 injurious ; they gnaw the roots of grasses and corn. See on these wireworms 

 KIRBY and SPENCE Introd. to Entom. I. pp. 180, 181, and WESTWOOD, 

 Modern Classif. I. p. 238, and the authors there cited. 



Amongst the numerous exotic species we note only Elater (Pyrophorus 

 ILLIG.) noctilucus L., VOET Coleopt. i. Tab. 43, fig. 16; it has on each 

 side of the thorax a smooth yellow spot ; by night it emits a clear light, 

 which radiates principally from the spots on the thorax (comp. TKEVIRANUS 

 Biologie, v. s. 100 103, 475). This, with other phosphorescent species (see 

 KIRBY and SPENCE Introd. n. pp. 410 412), is found in South America. 

 Comp. GERMAR Zeitschr. f. Entomol. in. 1841, s. i 76, J. CURTIS in 

 Zool. Journal, in. 1828, pp. 379 382. 



[A fine specimen of Elater noctilucus, which had been imported in a cargo 

 of logwood, came into VAN DER HCEVEN'S possession after it had lived some 

 weeks in other hands. He kept it alive for a fortnight. The phosphorescent 

 spots were, in the dark, first blue, then emerald green, then incandescent. 

 Large printing could be read by the light, but it was necessary to carry the 

 insect along the lines to read continuously. In oxygen gas the luminosity 

 was not more splendid. Experiments to determine whether the tempera- 

 ture rose with the phosphorescence were interrupted by the death of the 

 animal. On dissection, nothing peculiar was observed beneath the spots on 

 the thorax, except . large or smaller masses of the adipose body connected 

 by numerous tracheae. The Professor thinks it not impossible that the 

 production of light may not be confined to a particular region, but may 

 occur wherever the adipose body occupies the spaces between the organs in 

 sufficient mass, and is adequately supplied with air-tubes. The two spots 

 on the thorax, though destitute of the brown colouring matter, are of the 

 same thickness as the neighbouring integument. Does this thickness, the 

 Professor asks, account for the transmission of the green light, whilst that 

 which proceeds occasionally from parts of the inferior surface, where the 

 membrane is thin, is yellow ? However this may be, the adipose body must 

 be very unequally phosphorescent, otherwise the light from the under 



