94 
ments this striation is not apparent, and the membrane is much thinner. 
In still younger segments the eggs are considerably smaller and the 
shape is commonly oval. 
A number of authors give the sizes of the eggs as follows: 
Dujardin (lS45a. p. 579); Outer envelope. 62 to 74 inner envel- 
ope. 41 to 42 /<: embryo. 32 to 36 hooks. 15 to 17 
IVeinland (1S5S. p. 55): Outer envelope. 54//: embryo. 24//. 
Leuckart < 1886a. pp. 661-663. from Weinland's material): Outer 
envelope. 60 //: embryo. 30 //: hooks, 17 //. 
E. Parona (1884): Outer envelope. 58 to 68 //. 
Grass! (18881): Outer envelope, 70 to 86 //: embryo. 36 by 28 u: 
hooks, 11 //. 
Zschokke (1889). no measurements given. 
Leidy (1884a. p. 110): Outer envelope. 72 //: a few oval eggs 80 by 
72 //: embryos. 4') by 32 //. 
Magalhaes (1896): Outer envelope, about 59.5 //: embryo, about 
34 //. 
Sonsino (Sonsino A Zschokke. 1896): Outer envelope. 75 u and 80 
by 75 //: hooks. 14 //. 
In measurements which I have made of eggs of specimens, both 
from the rat and from man (LeidyVs material), the outer envelope 
ranged, in both cases, from 64 to 80 //: the inner. 24 by 20 // to 36 by 
28 //: the hooks, 14 to 16 //. 
The middle pair of hooks differed from the other two pairs in the 
same manner as mentioned above in connection with H. nano., namely, 
they were more delicate and the ventral root was only very slightly 
developed. 
Besides the eggs of ordinary size it is not uncommon to ffud in 
mature segments now and then an egg considerably smaller, round or 
slightly oval, with the outer envelope much thicker than is usual in 
the larger eggs. Four such specimens gave sizes ranging from 40 by 
40 // to 40 by 48 //. 
Sonsino (Sonsino tSc Zschokke. 1896. p. 939) has found that the ova 
will remain alive in water at least fifteen days. 
DEVELOPMENT AND LIFE HISTORY. 
It is to the observations of Grass! A Kovelli (1888b. 1889a. 1889b. 
1892a) that we owe our knowledge of the life history of Hyrneiiolepis 
diminuta. Their results (as given in Grass! c'c Eovelli. 1892a. pp. 
31-33. 90-92) are as follows: 
All attempts at direct infestation resulted negatively. 
The cysticercoids were first found in the larva of the meal moth and 
its adult {Asopia faniiaUs). then in young and adult earwigs {Anisola- 
his anmdipes Lucas), and finally in adults of beetles (AG-s spinom 
(Linnaeus) and Scaurus .^tr iotas (Fabricius). They live in the abdom- 
