304 
JOURNAL OF ECONOMIC ENTOMOLOGY 
[Vol. 13 
determine the length of the prepupal stage, heretofore unrecorded, 
and the exact dates of pupation and transformation to the imago. 
In general, it may be said that the results corroborate those of Davis 
in that a decided variation of length of the larval stage occurs in most 
of the species observed. Thus, some species have in the latitude of 
Kansas either a two or three-year life-cycle. 
Species Concerned and Relative Abundance 
The seven species under consideration are L. crassissima Blanch, 
(fig. la), L. rubiginosa Lee. (fig. 2), L. futilis Lee. ( gibbosa Horn), 
L. rugosa Mels., L. implicata 
Horn, L. vehemens Horn, and 
L. submucida Lee., named in 
the order of their abundance at 
Manhattan. 1 
Sanders and Fracker (1916, 
p. 256) have shown that a re¬ 
markable variation in the distri¬ 
bution of the different species of 
this genus may occur within a 
distance of thirty or forty miles. 
The data herein given may thus 
be only applicable to the vicin¬ 
ity of Manhattan, Kans. 
L. crassissima. —This species 
is the predominating one of the 
night-flyers in the area under 
consideration. During the past 
four seasons 15,655 specimens, 
or 32 per cent of the total collec¬ 
tions of all species (47,494 speci¬ 
mens) were collected at lights, 
on food plants and in the soil. 
Over 99 per cent of these beetles 
have been taken at lights, 
although regular collections 
have been made on some forty 
species of plants. 
L. rubiginosa. —Ranking sec¬ 
ond among the nocturnal Lack - 
nosterna of this locality, this 
1 L. lanceolata is the most prevalent species in this vicinity. It is excluded from 
the above list and following discussion because of its diurnal habits, although its 
collection numbers are included in the total collections and percentages based thereon. 
Fig. 11 .—Lachnosterna crassimana Blanch; 
A, adult; B, egg; C, larva; antenna of 
female and male. 
