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June, ’20] HAYES: SOME KANSAS LACHNOSTERNA 311 
This difference in time of pupation produces a longer larval period in 
such species than in the normal forms. Perusal of Table V shows that 
the maximum length of the period in two-year grubs was 497 days (L. 
rubiginosa) and the minimum period 393 days (L. implicata) with 
averages for the different species ranging from 404 to 454 days. In 
the case of L. submucida (all two-year grubs), 687 days was the maxi¬ 
mum and 658 days the minimum period of development with an 
average of 668.6 days, giving differences between the averages ranging 
from 214 to 264 days. In other words, from seven to eight months 
longer are necessary for larval development in two-year species of this 
type. 
The three-year grubs pass through two winters and pupate the 
second season. A maximum period of 823 days was required for 
development in the case of L. crassissima, and a minimum of 732 days 
with averages for the different species varying from 743 to 773 days. 
A difference of 339 days is noted between the minimum larval stages 
of the two and three-year grubs. 
From the data at hand, there appears to be an alternation in the 
appearance of the two and three-year grubs; e. g., among the genera¬ 
tion of L. crassissima hatching in 1916, 85 grubs were reared. Of these, 
71 were two-year grubs and 5 were three-year grubs. The generation 
hatching in 1917 produced only three-year grubs. This difference in 
the case of L. rubiginosa was not so marked. In the case of L. rugosa , 
only two-year grubs were raised from the 1916 brood and the 1917 
brood produced only three-year grubs. Field collections made during 
the time of this study indicate a close correspondence to the broods 
A, B, and C, described by Davis (1918, p. 16) with 1917 as the time of 
appearance of brood A; 1918 brood B, and 1919 brood C. The alter¬ 
nation in the appearance of the two and three-year grubs in rearing 
cages, if true in nature, may be a contributing factor to the expla¬ 
nation of variations in size of the minor broods B and C, as for 
example, brood C is generally considered to be smaller than B. The 
1916 brood C at Manhattan was on the whole much larger than the 
1918 brood B, and may be due to the variation in time of appearance 
of the greater number of two and three-year grubs. 
The Prepupce 
The prepupal stage begins near the close of larval development when 
the grub sheds its meconium and assumes a quiescent stage preparatory 
to pupation. This stage was found to vary from 3 to 30 days with 
averages for the different species varying from 6.9 to 9 days. The 
maximum, minimum and average prepupal periods for the seven 
species are shown in Table VI. 
