594 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. 57. 



In ThrosGus the presternal plates are separate, connected with the 

 prehypopleural rods, which interiorly continue into a long rod-like 

 hypopleural apodeme. The anterior basal margin of coxa is sep- 

 arately chitinized, forming a curved rod, which posteriorly terminates 

 as a little projecting hook. These rods are also present in the 

 Eucnemids. The most interesting structures, however, present in 

 both families, are the paired, rod-like sternal (sternellar) plates. 

 Similar structures do not occur in any other Cleroid, but they have 

 their homologa in the two strongly developed, broad plates which 

 cover the whole ventral side of prothorax of the Buprestidae. 



The Throscid-Eucnemidae constitute an isolated, highly specialized 

 group inside the Cleroids, undoubtedly closer to the Elateridae than 

 to any other family of the series, but on the other hand not right 

 away to be considered a transformed and reduced Elaterid type. 

 Rather may a strong convergence toward the Buprestidae be empha- 

 sized. In fact, *he Throscid-Eucnemids can hardly be separated from 

 this latter family by any other valid character than the different 

 shape of the spiracles, the Buprestidae having cribriform, the Thros- 

 cid-Eucnemids bifore spiracles. It may, however, be advisable to 

 mention in this connection that, among the Cleroid, the Telephoridae 

 exhibit a type of annular-bifore spiracles with peculiar sponge- 

 like lateral structures, which recalls the large, crescent-shape air- 

 chamber of the cribriform spiracles. Thus the possibility is not ex- 

 cluded that some form among the Cleroid might be found with crib- 

 riform spiracles or some Buprestid with annular or bifore spiracles ; 

 a discovery which would involve the Buprestidae to be placed among 

 the Cleroidae. 



The Elateridae including the Cebrionidae are one of the best 

 studied larvae families.^ The Malacodermidae are by far not so 

 well known. They include groups of distinctly different appearance. 

 Some are flat, and smoothly chitinized larvae with laterally expanded 

 segments, othei-s fleshy, whitish, slightly chitinized, others again 

 darkcolored, soft, velvety pubescent. Labrum absent in all. Falci- 

 form, toothed mandibles occur in forms as Photuris and subulate, 

 often perforated in forms as Drilus; normally developed maxillae 

 with a single mala occur in most forms, but maxillae having stipes 

 completely fused with a chitinized mentum exist — for instance in 

 Lygistofterus ; purely bifore spiracles are present in the Lampyrids, 

 pseudo-cribiform in Telephorids; the ninth abdominal segment 

 varies greatly according to groups or genera; it is well developed, 

 soft, posteriorly rounded and without cerci in the Telephorids; 

 large, chitinized with distinct, blunt ending cerci in the Lygisto- 

 pterus; rather small, chitinized, and together with the large, cylin- 



' See Hyslop, J. A. The Phylogeny of the Elateridae based on larval characters, Ann. 

 Ent. See. America, vol. 10, 1917, p. 242. 



