THE MALE OF PLATYPATROBUS LACUSTRIS 
DARLINGTON (COLEOPTERA: CARABIDAE)* 
By Carl H. Lindroth 
Zoological Institute, University of Lund, Sweden 
The discovery of a new genus among the Patrobini from Lake 
Superior (Darlington, 1938) was most unexpected. It was founded 
on a single female from Batchawaung Bay, Ontario, in the Leconte 
collection in the Museum, of Comparative Zoology at Harvard, and, 
in the absence of a male, the author hesitated to state the true relation- 
ship of the new genus. This female is the only specimen of the genus 
Platypatrobus (species, lacustris Dari.) heretofore known. 
Quite recently, in September, 1961, Dr. Darlington and I visited 
the well-known coleopterist, Mr. C. A. Frost, Framingham, Mass., 
and, looking through his large collection, made the exciting discovery 
of a male of Platypatrobus lacustris , received by him from Dr. A. E. 
Brower. According to the label, the beetle had been taken at “black 
light,” July 30th, a few years ago (exact year not stated) at Sinclair 
in northernmost Maine. Its capture in a light trap and its well 
developed hind-wings indicate that it is able to fly. 
The new male, except for the two dilated basal segments of the 
pro-tarsi, matches the type completely. The extra setae on prothorax 
and elytra are considerably irregular in number and position : lat- 
erally on the prothorax are 3 (left) and 4 (right) (in the type 4 + 3) 
setae; on the elytra, 1st interval, 2 + 2 (type 1+2), 3rd interval, 
12 + approximately 9 (type 11 + 12), 5th interval, 10 + 8 (type 
5 + 6 ). 
I was allowed to borrow the specimen and have dissected the 
genitalia (fig. 1). The parameres are of the normal Patrobine type, 
almost identical with those of the two related genera, Patrobus and 
Diplous (Platidius) , that is, approximately symmetric with long, 
narrow apical prolongations bearing 4 setae at tip. The accessory sub- 
apical setae are inconspicuous, only 2 in number, and there is no 
suggestion of the hairy membrane externally that is characteristic 
of the septentriohis group of Patrobus. 
The penis (median lobe) is non-sclerotized dorsally, as in Patrobus 
and Diplous, but not entirely open, as in Deltotnerus , Platidiolus 
(Patroboidea) , and related genera. The hook-shaped basal part is a 
common feature of all Patrobini. The apex is long and slender as 
* Manuscript received by the editor October 26, 1961. 
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