NO. II LARVAE OF THE ELATERID BEETLES — GLEN I09 



logical similarity to E. decomtus larvae and because E. costalis inhabits 

 Finland. On the basis of adult characters, Brov/n (1930) reported 

 these two species to be very closely related. The larva examined is 

 the property of Prof. U. Saalas, Helsinki, Finland. 



Genus MELANACTES LeConte 



MELANACTES DENSUS LeConte 



Figure 40, / 



Melanactes densus is the only species of this genus that is known 

 in the larval stage. It is a western species, but the natural habitat of 

 the larva is unknown, the only specimen available for examination 

 being reared from eggs laid in captivity. 



On the basis of larval characters this species is a typical member 

 of the tribe Lepturoidini and should not be separated into a distinct 

 tribe as arranged by Leng ( 1920) . Superficial resemblances are found 

 in the larvae of Hemicrepidius, Crepidomemis, and Cryptohypnus, but 

 no closely related genera are known. The larva of M. densus (fig. 

 40, /) is readily distinguished by its large size, absence of eyes, seta! 

 and sculptural patterns, shape of the caudal notch, and the uro- 

 gomphi in which the inner prongs are small and the outer prongs very 

 long and corniform. The larva hitherto regarded by some writers as 

 Melanactes picens (DeGeer), originally figured by Riley and repro- 

 duced by Blatchley (1910, p. 771, fig. 292), unquestionably is not a 

 Melanactes larva or the larva of any other elaterid. 



The larva examined was not fully distended, but measured 38 mm. 

 in length and 4.75 mm. in breadth at 5 years of age. Fully distended 

 mature larvae undoubtedly would exceed 40 mm. Dorsum golden 

 brown ; venter paler ; lateral membranes large, creamy white. Caudal 

 notch large, transverse. Urogomphi short, robust, bifid ; prongs corni- 

 form, with sharp upturned tips ; outer prongs 3 to 4 times as long as 

 inner prongs. Ninth abdominal segment without a mediodorsal groove, 

 but with a shallow subcircular depression bearing 2 faint, short, para- 

 median impressions ; 4 widely separated setae on central dorsal area, 

 posterior setae being longer ; 3 blunt "teeth" on each lateral margin of 

 dorsal plate; tergite continues uninterruptedly on posterior ventral 

 surface for a distance approximating one-eighteenth total length of 

 segment exclusive of urogomphi ; sternum large, consisting of 2 

 sclerites separated anteriorly by a narrow median suture. Nasale of 

 I tridentate tooth, median denticle slightly larger than lateral denticles. 

 Frontoclypeal region broadly rounded posteriorly. One small dorsal 

 posteroepicranial seta just laterad to each side of posterior part of 



