Notes on the Immature Stages of Deltometopus Rufipes Mels. (Coleoptera, Eucnemidæ).*

Abstract

Larvae of the family Eucnemidae have been somewhat of a puzzle to entomologists since the first description of a larva of Fornax by Coquerel in 1856. The first American species were described by Osten Sacken, from larvae collected by Dr. Horn and an unnamed species from his own collection. The larvae are found in dead wood, some of them where it is still very firm, others, including the species under discussion, prefer wood which is more decayed. Although living in the wood, they differ very materially from the ordinary type of woodboring insects for they have no powerful mandibles such as these insects are provided with. Instead the head strongly resembles that of the leaf-mining larvae without having even as efficient mandibles as they. Schiodte quotes Coquerel as saying that they are “without perceptible organs of the mouth—nay without a buccal orifice.” It has been doubted by some authors, including Schiodte, that they were able to make their own burrows and were suspected of living in burrows made by other insects. The same authors also differed as to the food of such larvae, considering their lack of mouthparts, and Schiodte seemed certain that they must feed on xylophagous larvae and pupae, since it was quite evident they could not feed on wood. Some have thought they lived on the sap or “juices of the wood.” Little has been added to our knowledge of the larvae or pupae since Osten Sacken’s paper was written. Since these larvae seemed to be such an entomological puzzle, I have been much interested in collecting them from time to time in the last five years. Altogether three species have been collected, but only one or two specimens each time, and all my attempts at rearing them have been unsuccessful. Mr. H. G. Crawford, however, found one of these species very abundant at Guelph, Ontario and succeeded in rearing a number of adults. I am. greatly indebted to him for placing all of his material at my disposal, and also to Mr. Charles Dury, of Cincinnati, who identified the species for me as Deltometopus rufipes Mels.