150 Records of the Indian Museum. [ViOr; Sarl 
dibles resemble those of N. dawnae, except that the right one is 
distinctly tridentate at its apex, the lowest terminal tooth being, 
however, a little weaker than the uppermost; the middle terminal 
tooth is the strongest of the three. 
The maxillae and labium resemble those of N. dawnae. The 
legs resemble those of NV. dawnae, except in the structure of the 
stridulating organ, which is transitional between those found in A. 
voepstorfi and N.dawnae. The ridges on the second joint of the 
third leg are weak as in the latter species; but there is a row of 
special tubercles, as in the former, on the basal joint of the second 
leg. Similar but stronger tubercles are found in Aegus roepstorffi, 
but they are absent in Nigidius dawnae. Small tubercles are 
present on both sides of them in the present species, however, and 
oa one side of them only in Aegus roepstorfi. The stigmata and 
integuments of the thorax and abdomen resemble those of N. daw- 
nae and A. roepstorffi. 
This larva is not unlike the last—the only larva of its genus 
known—but the stridulating organ is more highly specialized 
along the same lines as, but to a less extent than, the stridulating 
organs of Dorcus, Aegus, etc. 
CUCUJIDAE. 
A list of the Cucujid larvae hitherto described will be found 
at the end of the account of the development of Uletota indica, 
Arrow (Rec. Ind. Mus., XI, pp. 353-358, pl. xxi, figs. 13-19).! None 
of these larvae bear any resemblance to the larva of Hectarthrum 
tvigeminum now to be described. The larvae of Hectarthrum were 
found in decaying wood with all stages of a weevil belonging to the 
genus Mecistocerus.? Often they were found in acavity of the wood 
witha larva or pupa of this insect, and sometimes with the remains 
of such. Other Cucujid larvae, although found under the bark of 
trees, have the appearance of actively predaceous insects. These 
have rather the appearance of lignophagous larvae. But in view of 
the circumstances under which they were found, and of the struc- 
ture of their mandibles, there can, I think, be little doubt that the 
reduction of legs and mouthparts which gives rise to this appear- 
ance is due not to their having adapted themselves to a diet of 
wood, but to their having become parasitic rather than preda- 
ceous.® ‘They must, however, move about in search of their victims, 
for the weevil larvae and pupae are not much larger than they are 
when full grown, and it cannot be supposed that one weevil larva 
affords all the food needed for complete development. 

1 To this list may now be added Herrick’s account of the habits and develop- 
ment of Silvanus suvinamensis in ‘Insects Injurious to the Household and 
Annoying to Man”’ (New York, 1914), pp. 236-239, text-figs. 70-71. 
* Mr. G. A. K. Marshall, to whom I am indebted for this identification, in- 
forms me that this weevil is near and perhaps identical with M/. corticeus, Faust. 
* Compare Wadsworth’s figures of the mouthparts of the endoparasitic 
Staphylinid larva, Aleochara bilineata, Fourn. Ec. Biol. X, pl. ii, figs. 14-18. 
