P. J. Darlington, Jr.
On the Dryopid Beetle Genus Lara.
Psyche 36(4):328-331, 1929.

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Psyche
[December
ON THE DRYOPID BEETLE GENUS LARA
Collecting at North Bend, Washington, in July, 1927, yielded a large series of the dryopid genus Lara, which was described in 1852 by Leconte (Proc, Acad. N. S. Philadel- phia 5, 1852, p. 42.) to contain a single species from Cali- fornia. Superficial examination showed at once that there were two species represented in the Washington material. Comparison with the type of L. avaru Lee. proved further that the insect I had at first identified as that species was at least subspecifically distinct, so that it is now possible to discriminate two new forms and at the same time to give a brief account of their habits.
In our fauna Lara is an isolated genus of the Potamo- philini, seeming to be, as Leconte says in the original de- scription, "the desired link connecting the anomalous Eury- palpus (Psephenus) with the true Parnidse. There are several apparent relatives, such as Disersus, in Central and South America, however. Leconte's description of Lara is sufficiently full, and the genus has been figured by Horn in the Trans. American Ent. Soc., 10, 1882, Plate 6, fig. 16. Key to the Species of Lu~a
Pronotum with the hind angles acute, but scarcely more prominent than the middle lobes; elytral pubescence uni- form L. gehringi
Pronotum with the hind angles acute and prominent; alternate elytral intervals with the pubescence less decum- bent, so that the elytra appear dark with sericeous lines. Size larger; elytra wider as compared with the pro- thorax; pronotum proportionately longer, narrower, and with more prominent front and hind angles. L. avara awplipennis
Characters opposed to those above L. avara avara



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19291
On the Dryopid Beetle Genus Lara
Lara gehringi sp. nov.
Text figure "a".
Black throughout. Punctuation and pubescence above and below almost as in Lara avara, except that there is no alternation of pubescence on the elytral intervals. Gen- eral form similar to that of L. avara, but the pronotum less strongly convolved and its side margins less strongly sinuate throughout. Hind pronotal angles only moderately prominent, scarcely more so than the sides of the pronotum a.t middle. Genitalia of 8 definitely more decurved apically than in L. avara.
Length to apex of elytra 5.7-6.5 mrn.
The 8 holotype and one 8 paratype are from NORTH BEND, WASHINGTON, July 28, 1927. One 8 paratype is Fig. 1. Outlines of pronotum and elytra of a, Lam gehringi; b, Lara avara avara; c, Lara avara amplipennis. All are magni- fied about 6.5 diameters.
from BARTLETT SPRINGS, CALIFORNIA, collected by A. Fenyes. The holotype is in my own collection, the North Bend paratype in the collection of Dr. J. G. Gehring, and



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330 Psyche [December
the Californian paratype is returned to Mr. H. C. Fall, who very kindly loaned the specimen to me for the present study.
The important diagnostic characters of Lara gehringi are set forth in the key. The Californian specimen differs from the other two in being a little more shining above. I take great pleasure in naming this species for Dr. John George Gehring, who was almost my first entomological correspondent, and to whom I owe my western trip of the summer of 1927.
Lara avara amplipennis subsp. nov.
Text figure "c".
Generally similar in form and sculpture, as well as gen- italia, to typical Lam avara, but larger, with the elytra a little wider as compared with the prothorax. The pro- notum is proportionately a little longer and narrower, with both the anterior and posterior
angles more prominent.
These differences taken together give the insect a recog- nizably modified appearance, although they do not impress one as being of specific value. There seem to be no external differences between the sexes.
Length to apex of elytra (amplipennis) 7.3-8.1 mm. (avara) 6.8-7.2 mm.
Length of an elytron (amplipennis) 6.1-6.5 mm. (avara) 5.2-5.4 mm.
Since the total length depends partly on the insect's position at death, the measurements of elytral length show the comparative size of the two subspecies more accurately. Holotype $ from NORTH BEND, WASHINGTON, July 28, 1927, in my collection. Paratypes: 49 8 8 2 $ from the type locality, July 27-31; 2 $ 8 from REVELSTOKE, BRITISH COLUMBIA, August 14, 1927. Paratypes in the Museum of Comparative Zoology, the United States National Museum, the Calif ornila Academy of Sciences, the Canadian National



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19291 On the Dryopid Beetle Genus Lara 331 Collection, and the private collections of Mr. H. C. Fall, Dr. J. G. Gehring, and the writer.
This series of amplipennis has been compared with the type and one other Californian specimen of true Lara avara in the Leconte Collection in the Museum of Comparative Zoology at Cambridge. For the privilege of making this comparison I am indebted to the authorities of the museum, and particularly to Professor Nathan Banks, Curator of Insects.
Horn speaks of having seen a specimen of Lara avara on a log under water in a swift stream. I found the genus only on log jams in large streams which were both swift and cold. The insects behave much like Psephenus, but are, perhaps, less alert, for they are usually found on the lower sides of projecting stubs or in crevices, just at water level. They are among the most resourceful of beetles in the presence of danger, for they can choose between craw- ling down a log into deep water, flying, or dropping into the current, which whirls them swiftly away. The ma- jority ride the current for a yard or two and then take wing. I owe my fine series of the genus almost entirely to a systematic but temporarily unsuccessful search for Amphizoa striata Van Dyke, of which North Bend is the type locality.




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